It doesn't actually levitate in-game tho, which is why I can't say I miss it too much even tho that was a much better ability than Cursed Body.
Haunter still levitates, and it's stats are still good enough to take on many of the same threats. It's stats are slightly worse, but still good enough, and if you want to you can somewhat alleviate that with Eviolite. Not a perfect solution, but at least Haunter has an actual purpose now, besides being a cockblock for those who can't trade it away for a Gengar.