weapon select would be pretty nice. You could earn new ones like you do in SC2. Before anyone jumps down my throat i'm not saying that MK should be exactly like SC. OK?

You could also, like you say, choose other items. Jax could have a selection of robot arms to use. Fast ones, and slower, powerful ones. Some of the guys could opt for heavy steel toed boots or trainers- the former giving more powerful kicks, at the expense of speed (both ground and leg speed). Girls would could select trainers or heels- the latter giving more damaging kicks and more reach, at the expense of ground speed. Moloch could have a variety of nasty things to stick on his arm.

These things could either be accesories, or just have different outfits giving the characters slightly different abilities.

Interesting idea, the tricks that it suggests. But I find that to place the private codes in the Kript still it is very better. To place in the Kript and not with idiotic codes of Gameshark, for example. I hate GAMESHARK!!!!!!