Re: Bowing in aikido
Wrestlers shake hands, some cultures think that's un-hygenic. It's cultural - we're in a Japanese martial art, that has been brought out of Japan by Japanese along with many of their traditions.
It's possible to go overboard - I've been in dojo where we were expected to watch in seiza if the shihan came over to help and was demonstrating with our partner, and then to do a bow in seiza. Others it's less formal. Something I've noticed, I think, is that the longer a shihan has been out of Japan, the more old-fashioned the reigi. Once, when in my friend's house in Tokyo, I did a bow from seiza when introduced to my friend's father - (I was early 20s at the time) - I finished, and afterwards his father asked the son to explain that he was a modern man and that sort of reigi wasn't necessary - handshakes were sufficient (and THAT was in 1977)
Dojo seem to me to be enclaves of old-fashioned-ness. Accept it or not, it's part of the "game" we play when we "play" Aikido. When (if) you're running your own dojo some time, you can do away with the reigi in normal practice, but it's a good idea to educate your students about what's considered proper if they happen to visit more conventional dojo.