I believe Pan to be the character that made the biggest difference in Dragon ball GT.
Pan is clearly responsible for Goku's (BASED) SS4 transformation. Pan is clearly seen in GT being helpful, cleaning using a mop, although I think a dustpan and brush would have sufficed, instead of erratically panning the mop around. Pan is also useful in cooking, Pan seen using a frying pan, however in my opinion, Pan would have better off using the frying pan to make pancakes, perhaps Pan had the ingredients for pancakes in the pantry.
I think that Dragon ball GT should have ended differently, with Pan taking over a MC.
But I guess we'll just have to wait and see how things pan out.