Maybe, but we'd definitely would be seeing the effects by now. Did you know that Rosalina's first spin-off appearance with Mario Kart Wii happend only five months after her debut in Super Mario Galaxy? Yoshi also became a series staple almost instantly, same with Bowser Jr, both appearing in spin-offs about a year after their respective debuts.
It's not really too early. In fact, we've already been seeing the effects, and the only real major one so far seems to be Pauline's resurgence as a major Mario character. And tbh, that's the only real major one I can see having an impact in the long run.