An important thing to recognise about Bayonetta is that the presentation of her sexuality is not incidental.
Not just to the presentation of her as a character, but to the moment to moment gameplay. To understand this you have to understand the genre of games Bayonetta is part of, spectacle fighters. A major part of spectacle fighter gameplay is that there are "flair moments", moments where there's a brief rest in the tempo of a fight whilst the character does a particularly flashy thing. Whether it's the over the top Obliteration Techniques of Ninja Gaiden 2, the fem-dom Torture Attacks and dodges into witch time in Bayonetta, Kratos' brutally demolishing a poor schmuck, whatever. They're moments in the game where the player gets to release a bit of tension not just because there's something cathartic happening on screen but because they are, in the good ones, temporarily invincible whilst it is happening (see: Space Marine, the execution moves did not render you invulnerable).
So, the sexualisation of Bayonetta is not subtractable from the presentation of the game as a whole without replacing it with something else.
This is an important reason why people are saying it is "done right", because it feels like a necessary component of the character and of the game as a whole, whereas in many other examples the sexualisation just feels so incidental, they're not doing anything in the game except being sexualisation, and if the game doesn't have the balls to go all out porn* they just end up being a bit tacky.
This is what grassgremlin is talking about with Ivy, not only is her sexualisation incidental to her character, it's actually contrary to what the narrative of her character purports to be, it's almost the ultimate in "doin it rong" when it comes to presenting a realistic and consistent character. (Plus by Soul Calibur 5 she's about 50 and should be tripping over those things)
*Srsly, I have played actual porn games which have less blatant fanservice during most of their content than many non-porn games. Seriously, if you told people one of these [https://www.youtube.com/watch?v=JodKGxAni8U] two [https://www.youtube.com/watch?v=zuCdI8w_N3c] games was pornographic and asked them to guess which, unless they knew the games they'd probably guess wrong.