So following Rayman Legends going multiplatform people are starting to turn to the game they want (or more like wish) on their platform. Long story short, Bayonetta 2 on PS3 or 360 isn't going to happen. You can look at other indications such as Ninja Gaiden II but there is something you have overlooked in that instance.
Confirmation that Nintendo is the one publishing this and they get the say if it goes else where came from the producer yet people still sit back and live in hope. Well this is false hope. The main targets of "proof" for the "inevitable multiplat" release are Ninja Gaiden Sigma 2 and Mass Effect. With Mass Effect Microsoft probably didn't see any value in the game anymore. But the people who point at Ninja Gaiden clearly overlook one strange fact. It runs on a different engine.
When the game has been published by the manufacturer it becomes a lot more complicated then simply going up to someone else and saying "publish it here please!" the manufacturer have the rights to publish the game. They get the say in where it goes. The reason it happened with Ninja Gaiden II - Sigma 2 is because Tecmo cheated. They ported the game on PS3 and then built it around the Sigma engine. Yes. Running it around the Sigma engine is the key reason they got away with it. It is a different game. This article will explain how it happened.
As the article explains Sigma 2 is a different game on paper therefore = like Gears of War or MGS4 Bayonetta 2 will that Wii U instance where the game stays exclusive. But there are bigger pictures here that you need to think about. To Nintendo, Bayonetta 2 could be their "revenge" for the games Sony and Microsoft "stole" from them.
Final Fantasy was a series which enjoyed it's retro success on Nintendo platforms. In fact FF VII was originally an N64 release before cartridges got in the way. Then the series double crossed it's former daddy and turned towards a fanbase which didn't have any knowledge of it (as Bayonetta 2 is doing now). Interestingly enough the same can be said for Ninja Gaiden. That was a series which enjoyed it's fame and got to where it was because of Nintendo. So before you throw dirt balls at Nintendo's garden do remember it happened to them and their fanbase. The difference is their fanbase have gotten so used to it they probably see Bayonetta 2 as a breath of fresh air.
360 and PS3 owners have constantly laughed at the Nintendo fanbase. Every time Nintendo fans ask for a game like UMVC3 or GTA IV they get told to go and buy one of the others if they are that desperate. Now Nintendo give you a reason to buy their system, a reason the system can stand out suddenly its a crime against humanity. Why are the people who laughed at the Nintendo fans that wanted those games special? Why don't they go out and buy a Wii U for it like they said to all the Nintendo fans that wanted those games? If they really care about Bayonetta or it's future as a franchise, or are simply gamers and don't care about platforms, they will take their own advice and man up.
Bayonetta 2 will not get on the others. Confirmation from the producer comes in and still people want to believe. But there are problems even if it could cross there. Firstly, if the game flops do you really think another company is going to go out of their way to publish it on something else? The game flopped on PS3 and 360 and the sequel flopping on Wii U would just indicate there is no future for this franchise. The reason it is on Wii U in the first place is because Nintendo was the only one wanting it. Nobody else was going to publish it. It would have been in a barren wasteland if they hadn't shown up. And would you really think sequels would happen if this flopped? No chance. All hope is on you and how much you really want this game. So the question is = do you want it?
If yes, you will have no gripes with getting a Wii U to play it. If you truly care about the game or the future of the franchise you will buy it. If not you clearly aren't desperate to play it or don't care about what really happens.
Seeing the game sell would convince Sega that a third one would be worth going through with. Then they will be able to put it on what platforms they want. But in this instance it isn't going to happen. Even if there was some secret loop hole that someone could find, by the time it happened whoever would step forward to publish it would use MGS4. They would assume anyone who really wanted to play it has played it by now and it just isn't worth the cost of porting to other platforms. It would already become difficult because of the gamepad anyway.
Nintendo are holding the fanbase at gunpoint and forcing them to buy their system but this has also happened to them much more often. I fully agree it would be better if everybody got a piece of the pie (see RE Revelations). If everybody got the game everybody is happy. But these companies put money first. That is the problem here. Truth is Bayonetta 2 would have happened on PS3 or 360 if somebody had stepped forward. But nobody cared. Ironically, its just like where FF VII would have happened on N64.
To wrap this up I will have you guys know that I am totally against money hatting and monopolies but every side of the fence has done this. It just seems strange Nintendo would suddenly change their policies and start writing contracts. There are Nintendo only owners that (while they thrive on Mario or Zelda) want more stuff to play. So lets be happy for those guys.