Anyway I think the key word for elegance is simplicity. Minimal movement delivering maximum effect and that pretty much matches the wikipedia definition. I have seen some Aikido demonstrations that had all sorts of extras that destroyed any sense of elegance and some brutally simple moves that were the height of elegance. Strangely (or perhaps not) the most elegant moves I've seen were in unscripted randori whereas human nature being what it is - the concept of elegance was destroyed with the martial flourish in demonstrations. This I think is true in Judo, Karate, name your flavour.
I can think of one name which can't be contested.
His techniques are tried and tested in randori. His movements are the most brilliant I have seen in a realistic setting ranging from the simplest to most advance techniques. There is nothing artificial in any of his movements.
The commonality with mifune sensei, saito sensei and osensei, I consider them technicians of an art.
I guess that they have elevated their art to perfection that they don't need sophisticated, flashy movements to look awesome that one is elated even with their simplest movements. We should be able to equate elegance with perfection, which can be achieved in the context of japanese martial arts within one's lifetime.