People
Please stop using Ryu and Cloud as
justification for Banjo-Kazooie.
What do they have in common?
They're series that
were most associated with Nintendo in terms of consoles
but now with another console developer.
After "switching teams," they've put some spinoffs and "lesser" titles for Nintendo.
What is different?
Final Fantasy and Street Fighter are genre-defining series that have spanned many console generations with quality.
They (Cloud and Ryu) are, to some varying effect, icons of gaming history. Banjo-Kazooie became largely irrelevant after the buyout.
Cloud and Ryu are "standard" 3rd Party characters, not 1st Party for a competing company.
Banjo's GBA titles were approved because Microsoft had/has no handheld to have as competition. We got Street Fighter and Final Fantasy titles on both home and handheld consoles throughout their lifespans in spite of "competition" from Sony on PS1/PS2/PS3 & PSP/PSVita.
Cloud and Ryu were chosen as characters by Sakurai because he knew they would be hype for mass audiences but they not expected due to various reasons despite having "low requests." Banjo-Kazooie largely hinge on the idea of them being chosen from the ballot. The bear and bird would be a surprise for different reasons.
(Edit: Also, Street Fighter and Final Fantasy are world-wide massive series. B-K wasn't huge in the east at its peak, let alone now.)
That's my opinion on the matter, and I think Banjo-Kazooie is one of the best games for the 3D Platformer Collectathon Genre and Tooie is possibly the best example of "how to do a sequel" for gaming.
Edit: To me, saying Cloud means Banjo-Kazooie are likely is like saying
means we're getting Inklings because they're customizable avatars from hit Nintendo titles that have a pre-defined personality.