You can resize d-pads already. Start/Select are not frequently used, so they are small - there is no place on screen to make them bigger really.
I thought about quick save/load as volume buttons as an option. Also L3/R3 on sixaxis would have the same function.
0, 90, 180, 270 degree displaying - on my list

Currently you can click to select area for the icon, but it should be achievable by moving too - it will make the process clear and easy -TODO