More of the same? Is that a bad thing?
Ever since I played the beta I like its theme and many of the quests and other activities.
I think the strength of WoW is, that one can do many different things in one world. If you want to solo and quest, do it! if you want to raid fine! WoW never disappoints you and always provides you with the environment for what you want to do.
Mists of Pandaria is no exception. It is interesting to explore, offers a different angle compared to WoW in general. So it caters to the veteran players.
to new players and returning ones, I suggest: just try it. If the concept of WoW appeals to you, you will be a citizen of Azaroth for a long time.
Yes, I know many thing that could be different. That could be improved. But if you like the concept of a large world to explore with many things to do....Go WoW