Re: Belt color importance
from what i've heard, this issue doesn't just stop with coloured belts. i've heard a couple of yudansha complaining about how other less experienced and/or lower ranking yudansha telling them how to (wrongly even?) do a technique at seminars (where they don't know each other).
that said, i think the issue is more about etiquette and ego - both which do not stop at coloured belts, or indeed aikido.
as to the original question about the importance of belt colour; well, it's as important as you want it to be i guess.