First things first: the map must have a valid author name, it can never be approved without one (Scenario -> map description -> "author").
The type shouldn't be Tower Defense, as there are no towers (in fact: why defense? You need to kill bases, right?)
Objects:
There's a lot to do here.
You didn't give heroes different proper names, you didn't even change the attributes (I could clearly see of which hero you based them, by just looking at the attributes and/or their proper name).
You must customize the heroes, make them different from the regular ones.
The spells are also very lacking: most heroes (if not all) only have 2 standard spells.
Spells are crucial to hero-games, just taking the blizzard spells is a really easy and cheap way out.
You focus on quantity WAY too much, you've got so many heroes, but not one of them is any good!
How about you reduce the number of heroes to... let's say 4 or 5 and actually put some effort into making those 4-5 heroes playable?
Quality > quantity, always and ever - do not be mistaken there, it'll cost you.
Gameplay:
This was downright horrible at the moment.
At the beginning, I picked "All Random", got the tuskarian and a hero chooser.
So I picked
Then I made some mountain giants, archers etc (units in general), they spawned near the mode choose-circles, so I picked "All-random" another... 10-20 times or so, so I got all heroes and all races. For 3 gold per hero and race (as an archer costs 3 gold), not bad, not bad at all.
I repeated this a few times, got about 100 heroes until I thought it was enough.
At this point, the game got completely useless.
I completely crushed any resistance I came across.
There's no need to continue this story, you clearly need to fix this massive bug (did you even test the map yourself?)
Terrain:
Everything is flat and boring to look at.
You've put some geometrical shapes of dirt in an area, blizzard cliffs around the sides and you're done.
Obviously this isn't good enough: give the players something to look at, something enjoyable.
I'll stop here, the triggers also need to be completely redone, but the things previously mentioned will take so much time that the triggers are the least of your concerns (and this comes from someone who values triggers as one of the most important aspects of mapping, so I hope you realize just how much needs to be done).
If you think you're ready to update the map, leave me a message and I'll unlock the map.