I've been running LOTRO since beta on my iMac..no problems. Your MBP should work just fine.
Game wise, I agree with mDelaney123 pretty much. I hit the lvl cap of 50 recently but really only stayed from lvl 40 on because a friend of mine just didn't want me to quit. The game gets very tedious at lvl 40, quest require full groups for the most part, and theres lots of grinding to do if you plan to get your legendary traits, and class quest completed.
That said, if you're a very casual player you might enjoy it more than I did, I don't want to discourage you. The graphics are pretty nice in the game and it was fun for awhile. More content for higher lvl players should be added later this year. Best of luck whatever you decide.