I played the normal difficulty. What i assume most people will pick. And yes some people managed to lose in that game with "noob" difficulty, but those are the people who have their brains switched Off while playing. You shouldnt make maps for them, but rather to the common man who has his brains On. Good example is hadezown td that is very hard, and it got popular because of it.
And for the maze, well, if you know it can be faulty you should fix it or remove it. After all, it is what you have to face each time you manage to beat the td levels. And to be honest i was pissed after the maze, but i took couple of deep breaths and rated your map honestly. And if people are pissed after the game, you can bet that they dont want to play it again. Thats not the kind of expression you want people to have of your map.
As for suggestions, i'd suggest that you divide the builders. How many builders were there, i forgat but was it about 5-7? You should split them up in to two or three different races that players can pick. As said most of the builders were useless because the towers were pretty much on the same medium level so there was no point building them later on. And later on when you got plenty of resources you could just buy the builders for fun and see "well his towers aint amazing, i didnt miss anything", and you get to see all towers with one playing time, leaving there not many reasons to play the map again.
