Siegespell: Deals lower damage in exchange for an effect with every attack:
This is... Too generalist for comfort, as it's not clear how it works out. Is it a random one of the effects each attack, or a research to alter every unit case by case, possibly one that's mutually exclusive with removing existing on-hit effects for improved damage? At any rate, my comments on each thing:
* Minion launcher: Creates a weak unit on the target.
SC2 Brood Lord, works well as a distraction method to redirect attacks from under-microed units and causes issues for melee units getting bodyblocked by the newly spawned ones.
* Napalm: Building takes damage over time.
* Termites: Target building or mechanical unit has negative HP regen.
These actually do the same thing, as negative regen is mechanically identical to damage over time, but Termites is more useful against units that have HP regeneration to start with, provided it's a set-to value, as it cuts off a source of health regeneration, increasing net damage.
* Fog: reduces building's range with every attack.
This is
weird, as it eventually causes a disable, but does it based on what can attack. If it bottoms out at melee, then the unit applying it may always be vulnerable by being close enough to be hit. Meta-wise, it means that shorter range units can work as
* Seed: Spawns giant roots around the building, slowing production and dealing damage.
Slowing down production is the weird part here, as stopping it is something that exists and is understood in metagame results (long story short, Frost Wyrm OP). The code behind
slowing down production is probably complicated as hell, and this basically acts as a means of messing with the enemy's overall capacity.
* Subterranean Tentacle: Every attack spawns a timed-life tentacle next to the building that attacks units and buildings. Cannot attack again while the tentacle is still alive.
Much like Minion Launcher, it distracts attacks from the attacking force, necessitating micromanagement and potentially blocking units. Unlike Minion Launcher, this is externalizing attack abilities, so the tentacle needs to be cost-effective in damage in its own right or be
really effective at screwing with defenders.
* Impaling Spines: Every attack causes an Impale spell between the attacker and the target.
This is the Lurker from Starcraft, but with added stun on those hit. Very,
very strong, as you've got a fairly easily controllable AoE that's difficult to precisely predict for the opponent.
* Meteor: Every attack causes a meteor to fall on the building, dealing damage and stun in an AoE.
This is a typical AoE on hit, but attaches a certain stun. Cleave+100% chance Bash in effect. This is
hugely problematic, but the structure restriction makes it more manageable by having a valid response in the form of keeping units distant from structures.
* Saboteurs: Target building becomes neutral once it loses half its total HP, whoever restores it to full becomes the new owner.
This is pretty close to the way that capturing units in Supreme Commander works (and is quite similar to the Queen from Starcraft Brood War infesting Command Centers). The result of this is that you end up being able to kill a base about twice as fast (if it's a passive effect on a unit), with a significant amount of available spending to claim the base as your own for less cost than building a new one, as well as acquiring the enemy's techtree at a significantly prebuilt level. In combination with some kind of combat engineer or high speed building repair, you can end up screwing over the enemy far too quickly for comfort. This is actually massively too powerful, as it effectively halves a building's health
and opens up the option to take it yourself, should you be victorious.
Slow burner: Low damage, fast/continuous attack.
* Upgrade: Damage increases by +1 every few seconds.
This is Void Ray from SC2. And WC3 health numbers are generally too large for the +1 damage to do much, IIRC this would at best improve damage by 16 per second. Significant, yes, but not enough for a serious research option.
Assimilator: takes chunks out of building HP and converts it into resources for the attacker.
So a dedicated Pillage unit? Slow, strong attacks which are below cost
anyways, but make up cost with resource stealing? Seems
nice, but it can cause problems with regenerating buildings, undercost repairs and other stuff that ends up making the resources around go up over time.
As you've proposed nothing but offensive siege stuff, I'll go with defensive siege things:
Live-in Repairman: Upon completing this research, your workers can station in your structures, gathering resources and repairing them for 10 HP per second.
Last-Leg Construction: This building costs 33% less to repair than to build and, when destroyed, leaves a wreckage that can be rebuilt at a 25% discount
