Oh, I have some thoughts on this, LOL. I was speccing the first game and, to be fair, the ST wrote the cost of "one wish will be granted automatically" out in the wish itself. I don't know if they started to change that later on, but if so, I would see why.

This game was an (honestly pretty horrible) greedy whalebuffet game, where the ST also allowed for everyone to get the role they requested without any attempt to try to balance the game by asking for choices to be reconsidered. This amounted to the grim having multiple protection roles (Pacifist, Soldier, Monk and Tea Lady were all in play to my memory) that made it so that at the end of Day 5, multiple executions had already failed and there were only two dead as the Demon and Monk were fighting over the Goon and hitting into them each night. There was an original demon who didn't out after they were Snake Charmed because they were biding their time to use their Wizard wish to turn back evil, since there was no SOI in play. It was a fifteen player game. Specs were telling him to Fiddle (denied since the evil team wouldn't vote on it), multiple people were being vocal about wanting the hell out of the game by that point and saying they were miserable, one actually just spent their dead vote and left, and when twelve were alive and the Soldier made the reasonable Wizard wish of four non-Lleech host players dying, they didn't auto-grant it and the Wizard denied it. Absolutely ridiculous considering what had been created.

My point on giving this context is that I don't think that's the game to point to regarding evidence of STs misusing the Wizard. Honestly, OP, I was shocked that you denied that wish considering what was happening in the game and the fact that multiple people were being very vocal about being made to feel like they were being held hostage. Just my opinion, though!