We already had Nier Collaboration
Platinum Games and Square Enix are close friend companies and have done many collaborations with each other in the past. it's not only HYPE AS HELL But also a very practical character inclusion that PGR will (revenue wise) benefits and everyone will enjoy
in terms of bosses and character roster it would be really cool to finally have people like Sephiroth in the same team as Vergil like we already have hypebeast characters why not more
Bayonetta is classy, sassy, sexy, stylish, fabulous perfect fit for PGR Waifu roster I'd dump 1K just for her even
witch time would also have a very nice mechanic considering its similar to matrix perhaps an even new set of effects just for her skins with matrix and witch time. And maybe the matrix has alot of other effects too
Sephiroth's magic would be awesome he would perhaps play similar to Luna oblivion and Crimsom weave a hybrid of the two
Both sephiroth and Bayonneta would have auto evade mechanics in their move sets to further emphasise on their stylish nature since that's how they fight
Sephiroth would have his one wing sprouting out going into signature mode and his final attack would be supernova
maybe he would have two final attacks one being a burst limit sword combo if he held the button and if he tapped it his full Safer-Sephiroth angel form supernova
bayonetta would have non stop climax has her signature transformation with her umbran madama fists being added into her moves due to her powered up state with madama butterfly being summoned for the final attack. maybe they can even add the kameha wave from bayonetta 3
There is so much to be done with this idea