There's no reason Bond shouldn't be black, though. There's no canonical thread that directly links Sean Connery to Daniel Craig other than a shared name and general theme. If we were to stick strictly to the terms of the books, Bond would be about 116.
Connery was identifiable as Fleming's Bond and the films were based on his writing. The films which followed Connery have been Bond in name only. His next incarnation could easily be black, Asian, female or a dog.
Ralph Fienes as the next Shaft ?
You’d think they’d have learned about the limits of adaptation with Idris following that comedy turd he served up on Sky recently.
Trouble is they have tried to link the character back to his origins (in particular in Skyfall), so it would be weird if he suddenly became black, while all the other characters remained the same. Though nothing to stop them completely changing direction as you say. Personally, I would go with a puma as JB - or a shark