I see this as a carrier issue and not a Youtube issue. Perhaps someone should benchmark and see how much bandwidth you need for the regular low quality video. It shouldn't be much.
My complaint is just that data connections on carriers are sporadic. You can get it for like 30 seconds and then it can pause for a solid 30 seconds. Even if you were getting great 4 bar reception and 3mbit downloads, the pause will kill you. I was working out to a routine I found on Youtube and it threw me off when Youtube died for like 1 minute trying to reconnect. I could've kept going but I didn't want it to come bakc and throw my routine off and then having to push teh time forward and wait for it to buffer again. Shrug.
Youtube already sucks for bandwidth issues (they've come a long way to improve that) even on wired connections. I've seen too many times where I struggle waiting on a 20mbit connection or something. I mean what do you expect on a mobile connection anyway?