That kind of design would require a lot of newer features, and multiple ways to play the game depending on the type of phone:
A new phone with motion sensor, so when tilting phone the char moves. This isn't an absolute requirement, but using the touch screen to move around with buttons may be limiting depending on how many fingers can press at once on the touch screen.
As it is, I think devs are looking at PC and *maybe* consoles, since it'd be the closest and easiest port to do without an overhaul on the design of the Game/UI.