I don't think the vanity pets are the cause of lag on the servers tbh. This is also a common MMO feature that many players enjoy. I can't side with cutting them from the game.
I don't always drink Skooma, but when I do I go to the Southwall Corner Club. May you walk on warm sands my friends.
Geeshe, no one has to have them. I really like mine, and I like to switch them out. Different pets suit my different toons. Just don't get them if you don't like them, but let's keep them for those who do.