I really do think this, the main problem with the playability of smartphone games is the lack of a direction input, not so much the lack of buttons.
The thing I don't think those bulky controller add-ons with SNES style buttons layout/full size d-pad/analog sticks .... I mean really no one is ever going to really use those. Not one wants a smartphone that looks like this
The main problem with smartphone games IMO is a lack of directional input. Even a small joystick (Vita sized) or a trackball would make many games far more playable, maybe a form factor more akin to this:
Not one would really look a device like that as anything odd. Maybe you could even add a A/B type buttons on the other side, but you don't need to go crazy with the control input. Even with just a directional input ...
Adventure games, even platformers, racing games, etc. would become instantly a lot more playable and it wouldn't really take much. I wonder if a company like Samsung or HTC will ever realize this. You don't need the kitchen sink here, even just a directional input would be a game changer if was standardized on a popular line of phones (like the Galaxy series).
