It's just that SNES users are quite picky about having their NTSC or HQ2x filters. It's easy to say you don't care, but you can't very well test every last game ever made yourself. You'll need to get some hardcore fans to help you with that.
I guess it sucks to be us, then.
MESS and MAME ostensibly use an "If you build it, they will come" mentality - once a driver is considered relatively complete, eventually someone will wander by and try his or her favorite obscure game. And since that person will be trying MAME or MESS, that person is typically smart enough to track down the right forums and report the bug. It's slower, and more appealing to the lazy.
