I have to admit, I was amused at the prospect of having my small army of pets out and about, but from what Enaress has observed, doing this does have a tendency to contribute to the lag in Shattrath (which seems to be especially noticeable with complicated pets like Lil' Smoky). I don't think I'd try it for myself; Shatt can be bad enough during server high time. But there's something about the notion of my Druid as a dedicated cat-herder or, say, an Undead being followed by a swarm of cockroaches, that just made me laugh.
One more thing; would the Disgusting Oozeling's aura stack, you think?
Gallery: Infinite pets bug