FFXI didn't have the ability to jump either. And the game mechanics didn't really require you to be moving all the time constantly like this game's fight mechanics.

KB + Mouse is the most effecient way to play, hands down. I can understand if you are physically disabled why you would want to do this, but you could opt for a different approach all together. Get a replacement for both, like this
http://gizmodo.com/307029/belkin-n52...+handed-gaming

Which is designed to allow you to play with one hand without the KB and mouse.