I can't 100% vouch for the view of the holiday firework shows from the hotels, but the regular show is not nearly as visible as Wishes used to be. The newer shows rely on castle projections, so you lose all of that. The newer shows have less fireworks than the older shows did, still quite a few, but not as much as in the past. The holiday shows tend to have some special fireworks though, so it is still worth seeing if you only feel up to watching from the hotel. These days, I'm not a fan of the parties, but if I did pay, I'd probably feel inclined to try to stay for it, given how much they cost.
Then again, that is why my last party was my last party. When last I went to one, most of my family did not feel up to staying for the whole thing, and it felt like a waste of money. That was when the price was quite a bit less.