...would they all have to train the same, eat the same food, etc?
If you want to regulate what they wear for the competition itself, fine. But I don't see how regulating what they wear while training is different than regulating what exercises they do while training, what their diet is while training, etc.
I was talking about competing. I don't care how they train. The purpose of competing in the event is to win, and in those circumstances, gear should be normalized as much as possible. There are always going to be differences in size, strength, etc. The purpose of the competition is to find the best in the world, and gear prevents at the competition that if some teams have items that give them a huge advantage over others.