Not sure if humility has that much value. Honesty with a true perception of yourself is much better. I've personally not noticed a difference in humilty between martial artists. One thing is that children are probably less humble (and therefore clubs with more children may be less humble).
I do think doing single person kata can give people an inflated view of their capabilities (since the imagined attacker tends not to move). However I think, karate and taekwondo are undergoing as much if not more change in training methods as aikido is.
One thing I often see with aikidoka, however, is a belief in their own moral correctness!