I didn't get my MBP yet, but as an orignal D1 and D2 player, and from watching D3 videos and seeing what its like, its just a very super improved version of D2. A type of third person, top camera view RPG hack and slash. The only parts of WoW or an MMO in general you will see in this game (these features are shared across genre anyway) is custom gear, levels, grouping, instances, etc..
As for the performance. From the MBP specs, CPU's should be fine as long as you have at least 4GB ram. For the graphics, the AMD Radeon HD 6750M on the 15" series is really your best bet. That card I have used and as long as you don't max out the settings on any modern game, you will do fine. The Medium-High range is usually what that card can handle for most games. Don't even bother with the MBA and a game like that