Yoshi-P's Interview with Famitsu includes a few comments about AST

[Alahra]

I don't really want full control, because why would I ever pick anything other than Balance except in extreme cases? I'd rather they buff all the other cards to make up for it.

I agree, honestly. But the idea comes up in just about every AST thread at this point. Outside of potential balance concerns (oh hey, a pun), there's just not a simple way to pull it off logistically within the current framework.