It's not that she's "too sexy", it's that that's almost all there is to her in the newer splash art. To shamelessly quote myself:
Succubi gonna succubi, I get that. But that's one aspect of her. The old splash looked sexy, but also powerful and fierce. She's murdering someone in the splash, and straight up laughing about it. It implies not only that she enjoys the moment of the kill, but that she's so skilled she doesn't need to worry about drawing attention to herself (my headcanon is that this is what she looks like at the moment she uses agony's embrace). This was not a woman you wanted to mess around with, except she's dressed so provocatively that you can't help but think about it. And the fact that she's wearing actual clothes points to the kinda-human-but-also-not thing she always had going for her.
The newer splash... The fact that others are rushing into the room where she's made her kill implies that she got past all of them without being noticed, the wine on the ground (plus the rings and the crown, both to the right and on the person rushing in) shows that her rich kill was relaxed with her (if he even knew she was there), and her pose is right out of a porno. But the ferocity is gone, and we're now at the moment AFTER the kill, where she's relaxed and provocative again. It's all still kinda there (aside from the clothes) but its presentation is weaker.
(also, there's a slight blurring effect in the older art, giving the image the illusion of motion and making the shot feel more dynamic than it is)