I'd like my bobber to make a distinctive sound from that of everyone else's.
Is a distinctive sound worth more than a distinctive image? Or is the size of the bobber important - the fact it is so small means that sound becomes more important?
I think sound is hugely under-rated in WoW, precisely because "good sound" doesn't get noticed. It's a subtle thing that influences you without you actively being aware of it. Other people creating sound can break that: Like the train-set just before Alterac Valley starts. The only obvious example of sound being used to customize a character is Mekgineer's Chopper - the noise made by those bikes gets noticed. However, that still isn't true customization, because there is only one sound - it's just a rare sound that most characters don't have.
Traditionally it is not done in modern video games, because they use blocks of pre-recorded sound, which are difficult to manipulate (the Death Knight speech is an example of manipulation). However, games could play your computer like it were an instrument - rather than pre-recorded sounds, the computer plays a (musical) score. That opens up the possibilities for a lot more variations, because things like pitch can be altered by the program's code, rather than being pre-recorded by Blizzard. I wonder why we don't do that? Maybe sound programming requires a lot more processing power than I think it does?