I don't agree with Durant being more valuable or more impactful than Westbrook in 2016.
This is just regular season RAPM;
http://nbashotcharts.com/rapm?id=335911072Durant is 6th and Westbrook is 8th in RAPM / Durant is 11th and Westbrook is 4th in LA-RAPM. (That luck-adjustment is only a factor to shot variance afaik)
Engelmann's PI-RAPM numbers are for rs+ps and in those numbers;
https://docs.google.com/spreadsheets/d/1ZW5UBk5BwcrEhh4mEsWl_H1Y9QGTaMPaT4v6dSEIBIo/edit#gid=0Durant is 32nd and Westbrook is 5th.
I don't like looking at raw postsason +/- swings because lineups tend to be too situational to account for in raw numbers. If Durant was as impactful as Westbrook, he wouldn't fall that much in adjusted numbers.
And my recollection, eye-test also had Westbrook as the more valuable player on 2016 Thunder roster, not Durant. I also watched some games, alas no full games because I don't have the time to scrutiny entire 2016 Thunder postseason and my recollection did not feel inaccurate.
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1. 2017 Russell WestbrookThis is one of the highest motor, the highest effort seasons ever. He has a polarizing play style but it wasn't like he lacked quality. In the PI-RAPM numbers I mentioned, he was 33rd, he was still in top 7%. As someone who sees a certain correlation between productivity and impact (the way I see RAPM is that, it says "this player is this impactful when his on court production is this much"), this is one of the best seasons ever.
2. 2012 Kevin DurantI know that he was a better player in 2014 and 2016, but this is his most complete season in OKC. His PI-RAPM rankings in 2012 and 2014 are pretty similar, 14th in 2012 and 10th in 2014. The reason why I'm going with the 2012 version here is the offensive jump in the postseason. The Thunder were 2nd in ORtg in reg. season with +5.2 rORtg and +6.6 NRtg team on overall. Durant had 6.2 obpm. Then in the playoffs, the Thunder faced -2.1 rDRtg teams (3 of top 10 defenses in the league) on average and I feel like this average undersells 2012 Spurs team. Durant led them to an insane +10.3 rORtg (+9.2 rDRtg) against that competition with +7.3 obpm.
I feel like 2014 is the other possible choice for him with Westbrook missing half of the season and Durant leading them to top 6 offense with 8.8 obpm. 2016 is weak compared to these 2.
(Fwiw, something like 2014 rs + 2012 ps would made me have Durant over 2016 or 2017 Westbrook but his strongest rs and ps runs just did not overlap for various reasons.)
3. 2000 Gary PaytonNot his defensive peak but he was still a rather positive impact. And that coupled with his offensive peak, I think this is the season for him. Everything loves him, box score numbers and +/- driven numbers. Malone and Stockton were pretty old by 2000 but they were leading the Jazz quite solidly still and Payton gave them quite a fight with a clearly worse team in a bo5.
4. 1982 Gus WilliamsThis is how WOWY works for me.
1980 Sonics were +4.5 NRtg team with Gus.
1981 Sonics were -1.6 NRtg with only Sikma because Gus sat out due to a contract dispute and DJ left.
1982 Sonics were +4.1 NRtg team with Gus once again, even when the team lost DJ in the meantime.
DJ's departure and better offensive output makes me choose 1982 for the player.
5. 2019 Paul GeorgeI've always been quite fond of Allen's impact in 2005, but PG's weak to mid MVP level season just takes it.
HMs; 1969 Lenny Wilkens,  1984 Jack Sikma, 1996 Shawn Kemp, 2005 Ray Allen