To the original point... I think a breakout with any class/car allowed would be best. Anything to encourage someone getting whatever kind of car they want and being able to race it every weekend would do wonders for the hobby IMO. I don't think another class with strict guidelines would help anything.
I was able to lap about .8 slower per lap than the fastest current VTA with an old Novak 21.5 and a LRP sphere, cheapo batts in a T2. That tells me that for VTA at least, somewhere in the 10% per lap range is good to keep people able to use somewhat modern, yet old/cheap technology.