I like this game alot. Its not the most original idea but its the funnest imo. Btw heros come back by refilling their health to 100% NOT by getting a 4 or 5 match with their building.
The "bug" that people keep commenting about is not a bug. The choppiness you see is your computer trying to handle that many people. With 2000+ people lag is roughly 66% for me.
Instead of limiting building spawns(reducing benefits) or adding more space between them(requireing more sight, speed, and life to find and deliver resources), you should enable resources to spawn infront of buildings (or inbetween them without changing the spacing).
I love it! For some reason this game style reminds me of Sonic the hedgehog.(Idk why) As with all of the unity games thus far look sensitivity is the biggest issue. I would suggest putting some kind of user control on that.