Almost all of MMORPG out there is trying its best to become somewhat like the Diablo 2 series.. If you want a MMO that has as much skills as Diablo 2 has then I suggest to you the MMO that I am currently playing called Atlantica Online.. The game let you to control as much as 8 characters per battle and their skills as well.. You might be wondering how a MMO can be played with so many characters.. The answer is that Atlantica Online is not your typical hack-and-slash game which is for me too repetitive and dull,, and that its game play is turn-based much like what you see in a Final Fantasy game.. As I have said,, you can command multiple classes along with their skills which gives players the opportunity to experience the game fully.. Try checking this game out..
Here is their link:
http://atlantica.ndoorsgames.com/center/default.asp