I agree with Lee Z, no visible signs of seniority makes for a very pleasant training environment.
One of the clubs local to us had an interesting environment...it didn't sound very pleasant and no one graded but some people thought it was ok....then the instructor went and died after running his club for 20 years or so....and no one could take over.
Guys with 10 or 15 years experience had never graded or taught and no one had the confidence to take the club on.
So it folded.
Personally I've no major attachment to grades or belt colours....but the grading process itself can be highly beneficial to building a dojo and its future leaders, it can energise, provide short term goals and is a very useful part of the sometimes hard road that is Aikido.
For me a grading is only as valuable as the effort put into achieving it, for myself I always give everything in my own gradings and try to encourage my students to do the same. Once its done ....its done and practice starts afresh tomorrow.....but give me focussed targetted training against a pleasant practice any day.