I like having colored belts for the younger ranks. I DO think that it makes a difference in OUR culture for many people. It helps them feel they are accomplishing something along the way.
Where I come from there is only OUR culture, and my dream is for OUR culture to keep a sense of open communication. If some white belt is obviously more advanced than me, I will simply ask him / her, "What rank are you?" or perhaps the more British prim and proper "Which rank has been bestowed unto you m'lady?" The point is, I can go into any martial arts store I want and buy a black belt for $10. Whoop dee doo. I think belt colors are great for the more sport-oriented martial arts, but not for aikido. Aikido is not a sport, it is a way to reconcile the world and make all human beings one family.
Watching the practitioners of a Vietnamese form of karate (Chung Nu I think is the spelling), I said to myself, these guys and gals are having an intense mental, physical, and spiritual workout, and they look like they are having a hell of a good time as well. I don't know if they have colored belts or not, but -if so- maybe that is good because it helps remind them that they are partaking of a sport, and not training to be some kind of bone-breaking, real life heroes. If every martial art was aikido, I fear the world would be kind of a boring place. In conclusion, I vote white and black belts for aikido, and I've never done another martial art, so I have no fair vote in their decisions.