That doesn't make it overpowered or imbalance, it just makes it a strong unit. Sure, Ensnare is pretty tough to get around, however, Raiders themselves have LOW DPS and LOW HP. They're not exactly game winners if you mass a shit ton of them and have Ensnare.
DPS in the game isn't a statistic based on the unit's damage output from attacks. If you use Ensnare on a unit at the right moment and the result of the snare causes the unit to take more damage, then that makes the Raider add more damage to your army.
Likewise, having 3-4 Raiders supporting your army and chain casting Ensnare on an enemy hero can cause more damage than most other units are capable of. In fact, the only other ways to accomplish such a powerful focus fire effect is with hero spells or heavy air units, which both are much more costly and limited than the Raider unit.
Most Undead players don't bother expanding. T3 is so subjective that you can just bank and then make a shit load of units and decide the game on that. As long as you have a decent base build and decent micro, you won't lose if you turtle in your base.
This is why a lot of Undeads push Orc at T2 now, because it's quicker and doesn't let the TC/SH get to level 3.
These are not strategies that are developed by design intend but by design
flaw. Every race has the ability to expand to additional gold mines because they're meant to have the strategical option, but Undead expansions are weak to types of harassment that weren't common practice when Blizzard were still balancing the game (like Zeppelins in Teneras Stand).
Undead players have developed strategies to overcome this weakness, and that's what you're describing. That doesn't mean it's a good thing for the game balance overall, because it's still a strategy made out of necessity than strategical strengths. It doesn't mean the game needs to be rebalanced because we both know Blizzard no longer has (or means to use) the resources necessary to actively tune their changes as this patch's batch of very careful changes illustrate.
Players build T1 against Human for a reason: to stop expansion. Militia and Footmen are overcomeable. For example, the time it takes a Militia to Call to Arms, run to the 3/9 o'clock expo is half of its timer. If you're trying to deny the expo then just pull out, wait 5 seconds, go back in, focus down their constructed buildings and repeat.
I take it you don't scout a lot, do you?
First of all, En_Fueogo, if we're going to continue debating like this I have to make it clear that you do not strike me as that knowledgeable a player, so please refrain from making comments questioning my experience when you miss basic information like the armor type of tower structures. I'm not trying to offend you, but please be careful not to offend me either.
Now you began with stating that top players have agreed on the game's balance - if you watch some of these replays you will see as a fact that on these maps I mentioned, Human players frequently get away with early expansions despite the opponent trying actively to counter it because the Human player has long lasting Militia reinforcement, the guarding creeps are too easy to kill and the enemy player has to beat through the advantage of base defenses in addition to his normal unit army and stop the both cheap and easily repaired towers from finish construction.
The difference in a small and a large map is that Militia wear out faster the more they have to run, so the enemy player could simply wait for the Militia to expire before attacking, but on a small map the Militia reinforcement don't expire before the creeps are down and the towers are up.
HOW CAN YOU MAKE THIS CLAIM? YOU HAVE NO IDEA WHAT THE GAME DESIGNERS INTENDED. ADEQUATE COUNTERS TO WIND WALK ARE AVAILABLE IN ALL RACES:
Human Arcran Tower/Militia
Undead Dust at T1/Nerubian Tower/Acolytes can have imba micro in the mine if you don't suck
Night Elf Moon Wells/Detonate/Gold Mine micro
Orc Burrows
I can make the claim by knowing the game. Also, I was not talking about Wind Walking being a problem for base harassment. A good Orc player will typically creep a few camps while hitting tier 2, then as soon as the Shadow Hunter is out he will continue creeping while the Blademaster stalks the enemy creeping party with his invisibility.
If you know the game's history, you'll know that the changes to the Blademaster came near the end of the balance patches and the change that removed collusion size from the Blademaster during Wind Walk was one of the very last changes before Blizzard stopped actively balancing the game and it was left for the legacy team.
Because of this the Wind Walk change was never really probably tuned and the ability to, say, pick up items while invisible never became a problem until the invisible unit could also pass through enemy units, resulting in the creep's loot disappearing in the blink of an eye. It wasn't really considered either that the free movement of the Blademaster would allow the unit to stand closest to the creep while being entirely out of combat, allowing a player with good timing to use the backstab bonus to take the killing blow out of nowhere, outperforming even ranged nukes such as Death Coil.
And all these abilities come from a single hero skill. Wind Walk alone because of its unique untested mechanics ended up providing more utility than any other hero has in one single hero skill. Hero units provide strategical advantages like auras that increase the strength of your units and hero abilities that can inflect damage, heal units or cause various effects, but nothing comes close to the amount of strategical utility the Blademaster has. This single change alone shifted the Blademaster to the primary Orc hero putting the otherwise long-term favored Far Seer on the dusty shelf.
As I mentioned earlier, the countermeasures to invisibility were never designed to counter the full utility of Wind Walk because the full utility simply wasn't discovered at the time the counters were designed and tuned. For example, an item like Dust of Appearance is a limited charge item that doesn't stop constant invisibility, and instead has an area of effect and a limited duration - intended to stop normal units from becoming invulnerable through invisibility like Shadowmelding or Burrowing.
Furthemore, the race limits on the item also has nothing to do with the Blademaster, but because some races rely on invisibility in the early game - like Night Elf versus Human. If Human had Dust of Appearance in the shop, it would mean Archers and Huntress couldn't Shadowmeld during an early tower rush and that would be devastating to the Night Elf. Human doesn't lack Dust of Appearance because they weren't meant to be able to uncloak the Blademaster, which means the counter isn't even intended to stop an ability like Wind Walk and players just make do with what they have.
This isn't how WC3 works. All levels of play have consistent differences among them and have players who play "outside the box." Yes, Human players generally make an Arcrane Tower in their base. Is it to stop Blademasters? Yes. Is it to stop anyone that wants to try to harass? Yes. Do Humans only make it to stop the Blademaster? NO. It's simply a good investment to prevent harass. That's why Humans make Arcrane Towers against races other than Orc.
Your analogy is false in the sense that you make it seem anticipating things like harassment in build orders is a bad thing. It's simply a good investment to defend your base. A lot of players I'm sure have been in situations where they go to creep and then their base is under heavy T1 pressure from the opponent. When your Night Elf, if you don't block your base, you're going to probably lose Wisps unless you distract from your creeping. So what's an intelligent decision? Blocking your base.
As strategies develop of course the paces of the game change. I don't get what you're trying to put out here. Anyone can use any sort of combination of unit or building to win, that is the goal of the designer. I can go on Battle.Net and make 100 food of Mountain Giants if I want. This doesn't mean I'm fucking with what the designers want or what the designers intended, it just means I'm retarded and going to lose.
The first statement is a bit funny because you did talk about top players earlier, and while I'm on the subject a lot of top players do not bother to "BM proof" their base because base harassment isn't nearly as powerful as creep-jacking like I mentioned earlier in this post.
When talking about balance, we only talk about a maximum level of play because the differences in difficulty makes races imbalanced at different levels of skills (just as you mentioned Orc was often considered overpowered because it's a race that's easier to play). Unless the intend of balance is to make the game balanced at all levels of play (both average and "skill capped"), then you can only assume the game is meant to be balanced at the level of play where player skills no longer are a factor as you can't make balance changes depending on mistakes (e.g. "I'm gonna nerf Zeppelin harassment because this player forgot to focus fire the Zeppelin with his towers").
The truth that has emerged through the game's evolution is that most issues can be overcome by simply getting better, even if the odds are against you. You can stop a BM from creep-jacking your creeping party even if the counter is much weaker than the attacker and learn what to expect from an overplayed strategy.
But the other truth (that I'm trying to make you understand) is that you can't really say "the game is perfectly balanced" because it's not. Warcraft is a game with history and it has had many different stages where the game was played differently. You say that the present state is the most balanced state and imply that no more changes are necessary, but can you prove that any of the other stages the game has been through would not have come to be as balanced if they were left as the final patch like the last balance patch did?
If players were given years to learn to adapt to past cheese strategies as they have been given to the present it would most likely have resulted the same: Players come up with cheese strategies that work more powerfully than Blizzard had intended with their design, but because there were no "nerfs", the players were simply forced to adapt and base their game-play on the overpowered strategy by either using it themselves or countering it whenever faced against it.
Example: In every single present tournament, you see how top players try and overcome the most cheesy strategies. In every past tournament, you saw how top players tried to overcome the past cheesy strategies. The only thing that makes the present different from the past is that there are no more active balancing and the imbalance has simply created a new standard.
That means the game is balanced in the sense that you're willing to accept this new standard, but players who know of the game's history also know that it is just another standard set by another overpowered strategy with the only difference being that there are no longer anyone fixing the game. While you could interpret that as Blizzard considering the game balanced, you could just as well interpret it as Blizzard considering the game playable enough to cease doing major changes to old content.
In fact, it has long been an acknowledged fact that a game like Warcraft 3 can never be balanced and the only balance Blizzard has been trying to achieve is to make every race playable in the one versus one format at top level so that all four races could be presented as competitive (which is what they've managed to accomplish before ceasing their balance patches, despite the races not being that equally balanced such as Undead versus Orc).
Accepting that fact makes the changes in this patch a lot easier to understand, Blizzard acknowledges that there still are some large imbalances left in the game (such as Ensnare and Wind Walk) but major changes in an attempt to rebalance these abilities could easily shatter the race's ability to compete at high level (and a wrong nerf to units like the BM and Raiders really could shove Orc right down the food chain again).
