In and of herself, I don't mind Constance. I could see where she could be considered "plussing" as she does more stuff than her predecessor, and it is nice to see an original character created for the parks (she's the only one I can think of added to Disneyland in the whole decade of the 00's). Plus, that character being a darkly comic unrepentant serial murderess is pretty edgy for DL.
Let's look at the Old Bride.
Our Ghost Host has left us. We're on our own, "wandering" through the mansion. We're in the cluttered attic. Clutter is what makes attics creepy - the idea that something could be hiding behind any of that random old stuff. (And, when the pop-up ghosts were there, something was.) Then we come across the bride. Still, silent, except for that eerily still-beating heart. Who was she? Why does she look so forlorn? We don't know...this gives her a sense of mystery. There's something tragic about her - the lone element of the mansion that isn't played in some way for a joke, a nice contrast to the macabre humor of the rest of the ride. Attics are where disused, forgotten things wind up - perhaps that's why she's there. We move down into the raccous party in the graveyard, but the bride stays up the attic, just standing there with her heart beating.
In the new version, the clutter of the attic has been divided into piles for each of Constance's husbands. We are virtually taken by the hand and lead through her story. "This is Constance's first husband. She beheaded him. This is Constance's second husband. She beheaded him, too. This is Constance's third husband..." And finally... "Here's Constance. Here's the weapon she used to kill her husbands. The End." As theme park storytelling goes, it's not badly done, and she is still one of the darker elements of the ride, but she lacks the mystery and tragedy of the original.