If anyone has any suggestions for follow-up questions in the next survey, please let me know.
I think you should collect more info on people's hardware. At the bottom end, some may have only OCS/ECS, but probably a lot of those people have a >7MHz CPU and some fastmem at least. That's important to consider for any realtime action games that need a consistant high framerate. A little extra CPU speed would also be needed for software sound mixing to get >4 channels.
Maybe categorize it like this:
plain A500/600/1000/2000
ECS system with accelerator (and A3000)
plain A1200
AGA system w/ accelerator (and A4000)
680x0 Amiga with RTG
PPC Amiga
Also, regarding the question of price, I think it should be noted it's all about the game. I'll pay $50 or more for an excellent game, $20 for decent game, $0 for a crap game.