Re: Competition in Aikido
One can practice Randori as light sparring without competition. Randori as a free game, with both sides initiating on their own does not imply competition.
The same goes for competition and ego - one does not force the other, you can have competitions and have inflated ego, competing only against inferior opponents, or do some other manipulation to inflate your ego (One can hang his ego on one minor success when deciding the competitor was vastly superior). Or you could use the competition as a learning tool, keep fighting against better opponents, loose all the time and keep your ego down.
The same is true for non competitive groups. One can inflate his ego due to his success with a compliant partner, or check his ego and keep feeling frustrated at his poor level, after asking that cooperative partner to give him a harder life and a more realistic feedback (In the last couple of weeks, I am improving one technique using such practice. I don't gloat at success; I just ask to raise the difficulty level to one I can learn from).
A competition can be a test for some techniques, but one can not learn to improve the technique through it. A good uke can help you to do both.