I really no idea whether someone is already using the avatar I picked.
I just went ahead and chose what I liked best.
This is indeed part of the problem.
With the current system, newbies can not possibly be expected to know which avatars are currently in use. There are going to be duplicates, because this is a big forum (therefore, you cannot possibly know which avatars are still "available"), and most of the more popular cards have already been taken.
Yes, it is a bit of an annoyance when more than one user uses the same avatar -- but is it honestly worth making a fuss over?
I kind of have to side with Jangoo, on this one. The relic art is nice, xdude, but if you are going to complain about duplicate avatars, why not use a custom one? Even if you just edit it a bit, like vrt. I'd even make one for you. But it isn't very nice to complain about other users "copying" your avatar, when you have limitless possibilities, and they have very cramped options.