Nothing really changed. What driven you away is still there but with another name.
The bgs are full of bots and the current pvp season is pathetic, one of the worst till now. The sad part is that 5.2 won't change that.
The raids are acceptable, nothing really special. They become tedious quite fast.
If you decide to play you should keep in mind that you will have to farm religiously if you want to be on the same level as the others. Even for pvp.
p.s: the easiest way to have an idea is to search ( on google - on diferent sites ) for negative reviews about MOP. If you can handle those, you will enjoy the game.