I'm not particularly passionate about Haunted Mansion; it's just sort of an old standby that is fun to go on occasionally, but is more notable for its short or non-existent lines most of the year.
That said, I wouldn't be upset at all if the Hatbox Ghost returns and a remake of that entire attic scene is triggered by Hatties return. I think the disappearing head portraits go over 95% of riders, and you have to know the attraction history or its several fabricated plotlines from the late 20th century to understand what you're looking at.
In the 1970's and 80's, the attic was just a spooky place with a creepy bride with a beating heart. It didn't make sense, and it didn't need to, like the rest of the ride. It was just a creepy/spooky visual scene you passed through, no plot required. If they bring back the Hatbox Ghost maybe they can get rid of the ex-husbands losing their heads gag, which many people don't even pick up on in its current format.