My gut feeling is that Westbrook's season is being overrated.
Westbrook is averaging 31.0 ppg, 10.4 apg, 10.7 rpg, 1.7 spg, 0.4 bpg, and 5.5 topg. He is shooting .424 while leading the NBA in FGAs by a huge margin (almost 25%). His eFG% is .475. The shooting and turnovers have to negate his triple double stats to some degree.
However, Harden has similar flaws, shooting .440 and averaging 5.7 topg. And, while I think Lebron and Leonard are better, it seems hard to make the case for either of them over Westbrook based on numbers.