I wouldn't mind the iPhone getting a little bigger, first and foremost to allow a bigger battery. However, the thickness is currently just about perfect. I would go wide and taller, by only about 5mm each. The other benefit of course is to fit a slightly larger screen. In all honesty, it looks like they might be able to cram a slightly higher capacity battery into the current iPhone, especially if it weren't for that SIM slot. This is probably one of the reasons Apple were talking going go SIM-less with some carriers over the past couple of years.

With the iPhone's auto-correct you can type pretty fast, making all kinds of egregious mistakes, without it adversely affecting the actual output. I'm a total iPhone typing novice yet I can still get by quite well, even with the phone in portrait orientation.