I'd do away with Rising's ranking system before I'd add penalties for using items. That would be weird in a Metal Gear game which I don't think has ever penalized players for using game breaking items.
It's pretty great in Bayonetta I feel minus a few accessory over sights.
Problem is that they keep making games in that same style of Bayonetta without being Bayonetta. I think ranks are pretty boring in 101 as well and ranking in Rising is probably the least enjoyable way to play it for me.
Rather than focus on balancing them I'd like to see them move away from the linear ranked fight game structure in the future. Honestly I'm kind of tired of it.
I don't agree with the removal of rankings altogether. Even with the questionable balance in some of their games I still love going for ranks, I would be really disappointed if they were removed honestly.
They just need to create a better structure surrounding them, DMC has you go through a 20-30 minute chunk of gameplay with no crutches before you get ranked. In P* games you feel like you have to game the system by restarting and messing around with save files because the game doesn't let you consistently retry, sometimes it just autosaves and screws you over the second you find out that you were off by 100 points and got an A rank instead of an S. Just let me restart endlessly then because you know that's what people are going to do anyway, that's the way your game is designed.
They don't even let you see the requirements for the missions. In Rising atleast you know that going for No Damage and Zandatsus will probably be good enough but in 101 you need the Pure Platinum on time and there's no way to know what the requirement is beforehand. Sometimes they want you to drag the fight out and extract alot of combo points out of enemies and sometimes they want you to just kill as quickly as possible.
Again, they just need better transparency and balance. If you make a game where every encounter is ranked and you expect players to keep retrying then just let them retry. If you want players to go through the entire chapter without restarting then block them from doing so but make it fair. I love going for S Rank but I really hope they work on that aspect of their games in the future.