Keyboard as accessory--sure. It makes sense for some. Probably left to 3rd parties.
Detachable 2-in-1? No.
That will make sense in a far off future where iOS and OS X merge. Until then, it's still a useful niche for some, but not a niche I expect Apple to target
Some percentage of people realize a new model is coming. Any world in which sales did not drop would be one crazy world.
Plus, for better or worse, Apple didn't increment gradually, they waited for a big jump all at once. They're the oldest game in town%u2014until they're not anymore.
I'm not sure I'd call that "iOS connected" by any stretch.
I already take photos of written notes often, and contrast-enhancement is indeed a useful step (which I wouldn't get a specific app for, I'd use Genius Scan or something).
So, take iOS out of the picture. It's a neat memo board, I suppose.