I do agree that what you intend to assert is objective fact; however, if we are to analyze the logic, there is definitive precedent that thoroughly establishes that "slots" are not relevant to Sakurai. The circumstances surrounding such should be taken into consideration, of course. But that does not materially alter the "fact of the matter."
Indeed, she was planned as a character.
No. That is adhering to confirmation bias.
It depends on the definition of "new" game which is subjective. Either way, if your point was not that the series is eight years dormant, I fail to see what rationale you are trying to illuminate. Star Fox HAS a new-game planned, one that Sakurai was most certainly aware of. I would also argue that Sakurai intended to revive the series himself. So at the very least, the consideration for a new game would materially alter the fact of the matter in the same vein as the point you are advocating for, would it not?
I did not proclaim that it revitalized the series, I quite literally stated that it gave the game (Star Fox 64) new-found relevance.