Reading around I believe what happened with Sadulaev's move to 97kg was roughly:
- Russia is strong at 86kg (with Geduev moving there as well) while at 97kg its iffy with the retirement of Gadisov and Boltukaev's inconsistencies. So they asked Sad to move to 97kg despite the fact he is walking at 91-92kg. Sad basically gives them a medal at 97kg, some color that is. So Russia is stronger as a team with Sad at 97kg.
- However, the move is bad for Sad himself. He is 15-20 pounds undersized at this weight which is massive and increases his chances of losing and worse, injury. In reading his interviews, I did not detect enthusiasm from the beginning for moving to 97kg -- there was even an interview with him and Gadisov and Sajidov on this and Sad said that he isn't sure it makes sense for him. I think he wanted to do a match or a smaller tournament or two, but not permanently. But now that he accepted he has to stay put otherwise will look like he is running away from a challenge.
Nonetheless, I believe Sad will be a world champ at 97kg in 2018 -- I don't think 2017 is actually representative for him at 97kg for many reasons. I think Snyder , Baytsev, and others will have a very very tough time with him in 2018. I don't think he gets tired again in this way, is more used to 97kg, and taking Sad down from open space is super hard. I'd say 2018 is actually the year that is representative for him at 97kg so I am looking forward to see how he wrestles.
That said, this is for sure not sustainable. Rolling around with the bigger boys and constantly giving up 15-20 pounds, even if he wins, is just not great for his longevity in the sport and overall health.
The fact that Sadulaev lost one year after the Olympics has some merit. When Fadzaev moved up to 163 and wrestled Kenny Monday it was 1989 and Fadzaev lost a very close match. There are a lot of similarities with potentially one big difference. Fadzaev moved back down the next year. I don't know whether or not Fadzaev gave any interviews after the match or whether or not he claimed he was going to stay at 163 or not.