I'm with the OP. You want to make T5 enhancements ML8, make them ML8. You want to give fighters two fewer feats, give them two fewer feats. Don't make a byzantine system where ML4 pre-req enhancements require a feat that in turn requires 8 fighter levels (none of this stated in the enhancement descrption of course), particularly when that feat is useless and has a pre-req of an additional useless feat. That's just bad design.
I and I don't buy that 15M/5fighter is some big problem, you're giving up stunning fist to use weapons, and you're wisdom based if you want to use quiver palm so that increased crit range isn't going to really shine. Anyway, you can already swing around a Sireth with a 12-20/x3 crit range with T5 Heshin mystic... so that ship has pretty much sailed anyway.