Re: Is is it still Aikido if you take away the Japanese clothes, etiquette and other things?
So it looks like for most people the clothing isn't terribly important, but the etiquette is very important. Actions over appearance.
This is pretty much a discussion that can only be had with gendai arts like Aikido. The koryu arts are pretty clear about how much change is acceptable (not much. You either adapt yourself to the system or go do something else).
I will note that as far as I'm concerned, modern IJF Judo is almost a completely different animal from the Kodokan Judo from which it was born. They still use the cloths and the formal etiquette and the Japanese terms, but the spirit of practice has been transformed. The complete focus on competition and making everything spectator and TV friendly has created a completely different beast with a totally different soul.