Pluto is good for dark right now... because dark right now kind of sucks. If you speed up dark and burst faster (using Shingen and Osiris), pluto's requirement for blocks quickly makes her a detriment to the team because of how long it takes her to get them. She definitely needs an AW to lower her CDs if they ever bother fixing dark.

That said, what Dark really needs is something along the lines of Titania to pull some of their slower heavy hitters into the fast meta. At the moment, the only one that really works is Thanatos. Ideally, the line up would be something like Thanatos, Dark Titania (let's call her), Berith, Osiris. Should work well enough to not be a joke anymore at least. The rest of dark though... god knows, that's a lot of fixing (maybe that's why they don't want to touch it?).