Personally, the X/y co-ordinates are driving me mad. It's so goddamn hard to figure out where I actually am and where I'm going, and it takes forever for me to figure out what the hell my opponent just ordered. It get's to the point where I'll just do whatever's easiest instead of take a half hour to figure out what I'm/they're doing.

I could probably make sprites, and you could use numbers as opposed to letters. (12,25) for instance. I just can't think of things without fixed destinations for whatever reason.