What's wrong with making hard challenge steps for every song? Personally, I don't play enough dance games anymore that I can even do most of the ITG expert steps, but does that matter? You don't *have* to be playing on the hardest difficulty. If you liked the standard DDR-8/easy 9, play that on heavy, and let the people that like hard stuff play stuff on challenge. That way, there're more steps for all players of all skill to enjoy. I don't need bragging rights of saying I'm doing something on the hardest difficulty.
When I do go play with my friends, we usually pick ITG over Supernova, because some of my friends like the hard stuff. It kind of sucks, because I like the music in Supernova a lot more (despite crappy cuts), but we choose the machine that'll have fun difficulties for all of us.
And again, the new Supernova songs have terrible steps. Extreme added some new patterns in, but SN felt like more stuff I've done already. | 
