Right now, I've got it Harden, Lebron, Kawhi, Westbrook in that order.
I am in the NY area and watch lots of Carmelo. When you see Carmelo play a lot, you sort of understand when somebody's game is so overwhelming that sort of the force of the offense and how efficient it is is sucked out just from some player's presence in it. You see it with Carmelo, D. Cousins, and Westbrook more than anybody else in basketball right now. I think the Thunder should be better than they are, but Westbrook's sort of gravitational pull on their team disengages the rest of the players on the court. I'd never get rid of him because he's so freaking good... but his game is such that the rest of the floor is just a little more disengaged than they would be if they were playing with other elite PG's. Same thing happens with the Knicks...
With Kawhi... great 2-way player and easily the Spur's best and top 5 player in the league and it's not fair that the Spurs have another top 1% elite player in the league yet again after Robinson and Duncan. That said, the Spurs take a step back with no Kawhi but not NEAR what the other 3 teams would.
Lebron and Harden are the 2 most intrigal players to their team's successes in the league this season. They get way more out of their teammates in how they play than the other 2 while still dominating. This season, the race is between them at this point and I don't think it's close. I nod Harden because he's team lead and has clearly held team chemistry together better than Lebron and, frankly, the Rockets have just been better than the Cavs this season with a lesser team.