There's definitely an argument that allowing the Master to be reinvented continuously is the very thing that let Moffat do such a great storyline with Missy, and being tied down to that would prevent Chibnall or any future writer from doing a similarly effective reinvention.
I don't know, I'm reserving a lot of judgement about this episode until I see the conclusion. There's simply no way to tell how or if this interacts with the Missy arc. Like, at the moment, it feels weird to have the Master reset to, what, 35 years ago with the shrink-ray stuff when their redemption arc was a little over a season ago. Seriously, the last two-parter was when we previously saw the Master, that's not a lot of time for an off-screen reinvention. Add to the fact that both Harold Saxon and Missy were built up and built up with extremely direct, personal attacks on the Doctor... well, again, we need to see part 2, but at the moment, it feels like the Master is just wanking around being evil for laughs, without the same sort of personal obsession and vendetta that characterized their more recent appearances.