Here is my feedback from when we played today:
1. Your pop file is insane.
Really can't emphasize this enough. These waves are incredibly, ass-destroyingly hard. The later waves have too many spy and pyro bots, both of which tend to rush players in mobs, which leads to an un-fun clusterfuck while the other bots run away with the bomb. The earlier waves, especially the first tank wave, have way too many support bots and it makes it incredibly difficult to defend against them, especially when you don't have a lot of upgrades yet.
2. The middle is useless
Because of all the fences and other crap along the edges of the big central plateau, it's next to impossible to defend from it. Since players can't defend from the middle, they end up sitting at the beginning bridge area, and then falling all the way back to the final room when they get overrun. This combined with the extreme difficulty means that 99% of our playtime was spent sitting in the final room and turtling, which was made worse by the fact that:
3. The final room is bad
Once you're inevitably shoved back into the final room by ten thousand spy bots or similar, you're trapped in the final room. The big problem here is that the final room is almost completely isolated from the rest of the map. Once inside, you can only escape through one big door, which is the choke point where literally every bot is going to go. Even if you do get out, you're at the bottom of a big hole and the only ways out are by running up huge, coverless ramps directly at bots who have a >384 HU height advantage. You could really easily remedy this in 5 minutes by just cutting a hole in the wall at the top of the balcony in the final room, so players could get out onto the nice, big scaffold outside, and connecting said scaffold to the raised area next to the ramp on the left.
Also, people complained about performance issues during the more hectic waves, but I had no problem because my computer runs on liberty and liberty has infinite power.