Scaling feats are a great idea, but they do run somewhat contradictory to E6 principles - if you get a theoretically infinite amount of feats, they don't need to be all that great on their own. I remain torn on their use - some feats are so crappy that they just beg for scaling, and that may be justification enough. But they're more applicable in situations where feats are rare resources, therefore necessitating the boost.