My suggestion is to change the YOUTUBE BB code to YT.
This would enable users to add videos faster than normal without having to type the whole code, also would be nice for those who would rather type the code than pressing the button. Another alternative would be to have both codes, therefore people would be able to use the one they prefer. Obviously this is a minor suggestion and will not have a big impact on anything, it's just a nice addition that would be nice to have.
tl;dr:
Change [youtube][/youtube] into [yt][/yt]