Currently busses only get a letter "A B C...", which is assigned to it when you create it and you cannot change it later. When you use many busses, you need to have a separate "cheat sheet" just to remember what is what. If you could rename busses, everything would be much easier to keep track of.
Plus, with the way it's currently made, busses look too similar to color groups (which also have a little white circle with a letter in it). If their name was written at the top instead, they would stick out much more, apart from the color groups.