Yeah, I know it's unlikely about Bayonetta 2. But I'm holding out hope since some of the companies would probably like a bigger demographic than Wii U owners who want good action games.
As far as Mario Kart goes, other than the ones I haven't played, they all feel like Mario Kart to me. It's new and shiny with new tracks and such, but they've never really strayed far from their formula as far as I'm concerned.
To answer your other questions, take the Batman games for example:
Would you say the Arkham games are the same?
Arkham City and Origins are very similar. There's some differences, but a lot of origins is definitely pulled from City and it shows. I still like Origins better than City overall, but I wouldn't say there's a ton of difference between the two. Asylum to City there's a big change in structure though.
Now I'm not saying every sequel has to be new and innovative and change the formula up. I like games that do what Mario Kart 8 probably does. My point in saying that was partial hyperbole, but the core of my point remains -- Mario Kart 8 seems like another Mario Kart game. You know what you're getting, mostly, before you buy it. And as such, someone without a Wii U of his own would have to be a ridiculous Mario Kart fanatic to go out and buy it just to play it on a friend's system (however frequently).
As far as the new Zelda, it still follows the same formula as LttP -- there's the village area (with dungeon) and the lost woods (with dungeon) and death mountain (with dungeon), etc. However, being able to rent all the items from the start and tackle the dungeons in any order? That's noteworthy, even if some of the dungeons were a bit easy or short (which works better for handheld play at times).