I didn't really switch things around too much. All face buttons remain the same. I play on 360, and my layout is this:
Left Trigger: B+K - this allows me to use 4A and hold EIN, then use moves like UB 44B+K, or 66B+K easily.
Left Bumper: A+B - I use this once in awhile. I programmed this to compensate for my inability to properly nail the face buttons simultaneously, every time. It also makes holding EIN from 66A+B easier, and I can still kick with the face button. I'd have to use some funky claw-grasp in order to do it otherwise!
Right Trigger: B+G - It's important to be able to mix up your throws with ZWEI. I can't nail this throw with the face buttons easily.
Right Bumper: A+B+K - Placement makes sense to me, and feels good when playing. My B+K BE is just two clicks, and 1K BE feels natural enough.
I switch characters often, as I'm still learning the game. It's important that my layout is virtually universal as a result. The only issues I've had so far with this layout stems from some Voldo moves and most of Hilde's moveset.