Sounds like a good idea (I'm going to play devil's advocate)
So you drinnk water with stuff in it after you workout. You're supposed to drink water while you workout, and you're also supposed to eat properly after you workout. That would replace the proper nutrients you're missing anyways, shouldn't it?
It seems like a way just to get people who think water is boring to drink more water. Personally, I love pure unadulterated room temperature water, not cold, not warm or hot, just regular old water.