I have never played Ravenloft, nor read any of the materials for it (although I did play the AD&D Strahd adventure).
I'd like to think that, as a player, I would know the rules about what can and cannot be done safely in the campaign that I am playing in. If I were playing in a game where taking the most logical course of action "Hey, we finally have access to the most powerful magic we are going to get in our life, lets try to get out of this horrible place we we're trapped in" resulted in seemingly arbitrary smack-downs by the GM i'd probably just want to stop playing that game.
I've always thought that the "turning wishes into curses" trope was only appropriate when dealing with devils or other known evil sources where the player/character knows that they are in a very Buyer Beware situation. Finding a non-evil item that communicates to you that it can fulfill your wishes shouldn't have to be treated with the same kid gloves. Of course the item may not be able to fulfill the wish, but in that case I think it would be more appropriate for the item to let you know that "A wish that grand is well beyond my power, pick something else" rather than trying to hose the player.
Maybe in Ravenloft literally everything in evil and nothing can be trusted? If that is the case the players should be made aware of the fact that everything is Buyer Beware in the entire world in Session 0.
I don't see how expecting a wish to be a powerful boon is some sort of "modern players different expectations". A wish is literally the most powerful magic available to most characters in their lifetime.