The CCM is mostly a popularity contest.
One of the few that couldn't be argued is Priddis in 03. At the time I thought they would give it to Gower as compensation for the Dally M, or Sattler for "that tackle" But they got it right. It wasn't until I watched a replay that I realised how great Priddis was in that game. Too much nervous energy live to appreciate it for me.
On the more controversial ones, Fifita in 16 was best on ground, but Lewis was also immense, I was really pleased for him. The play where he was stopped centimetres from the line and he had the mental strength not to promote the ball was the play of the game for me. iirc they scored very soon after that.
2015 was actually one where a player from the beaten side would have been a worthy winner, but from the winning side Morgan was far better than JT.
I don't see Cleary as controversial. You could easily make an argument for Yeo, To'o, Edwards and Crichton, but it all goes back to one of the best examples of kicking a team to death you will ever see. The kicking was well supported by very committed defence and line speed, but Nathan has even just an above average game with the boot and Souths probably win that game.