First of all, Lion has made some major changes. Everything is now 64 bit. Any program that is not 64 bit is going to have running problems.
I'm running plenty of 32-bit applications with no issues. 32-bit applications run perfectly fine on Lion. If it doesn't, the issue is elsewhere, not with the application's bit-ness.
Secondly, Lion has really boosted its graphics requirements. Sure you can run it with a slow graphics card, but you may not like it.
Again, running Lion with a GMA X3100. Terrible graphics card. Some animations are a little slow, but nothing that's a big deal.
Those people who report no problems WHATSOEVER are almost uniformily running on more than 8 gb system RAM.
6 GB here. I know it's more than average, but from my memory usage stats 4 GB would also be fine as I rarely use more than 4 GB RAM.
I heartily agree with everything else you've said.