
When I beta'd and used a level 65 character the only zone I attempted to solo in was Corathus. Down towards the Undershore zoneline there were some blue mobs that weren't too bad (was playing a Beastlord though so everything was slowed). Aggro was...attack of the killer fish pretty much sums it up. I honestly haven't been back there since for anything other than the charm upgrade so I've no idea if the aggro is still all weird or not.
Monster missions are fun, if you have people to do them with. The zones aren't laggy to me but they are to others in my guild, guess it really depends on your machine + bells and whistles you have turned on.