Well, first I'd say, hey nice armatar you want there... but I can't see it. Second, people would be able to spam pictures... like adds for IPODS and stuff like that. They can also put inappropriate stuff in there too. Well if you are really bummed out. Go to support and suggestions and give your idea as an armatar.
It's cuz There could b inappropriate ones uploaded, and that would just be a bigger hob for the mods to monitor them.
Also AG has a medieval theme going on, and also animals. People choosing there own Avatars would kind of ruin these themes. Also the Armatars have there own flair and style which makes them cool.
Well they could. But it would be really hard to catch them. There are over 100,000 users. Monitoring and watching all of them and screening out the bad ones would be next to impossible.