atm my bot goes from 1 to 54 almost flawlessly, you're still going to have hiccups such as unmeshed areas.
the main issue with afk botting from 1-90 are the mesh issues, that's it... the flight path bugs are caused by addons which crash or freeze part of the code that allows you to take flight paths (very rare but I've seen it enough times to know), the stuck issues are now resolved with the new stuck handler, a plugin would definitely be needed if you got stuck in an area where the bot sits there forever (if all else fails, use hearthstone which is what I use)... player reports, down from the beta but still an auto reply wouldn't hurt.
also, if you don't like being ganked I'd recommend leveling on a Normal realm and then doing a transfer (plan ahead, see what free transfers are available)