Will this art style for an open-world game appeal to players?

Yes, I would play a game like this. I think this style reminds me of Torchlight, blocky in the same way although a lot less colorful.

I might play an open world game in this art style depending on what the story of the game is, how the combat is, and what kind of reviews it gets. If I just had to go off the art style alone with no other factors then I would say no, probably not.

I think that it would depend on the type of game. It's an interesting art style, but it needs more diverse textures and colors to make it more detailed and appealing.