Cindy McCain is not winning a DEM primary despite your sick fantasies. If she runs as an indie, she sucks the energy out of the DEM campaign and battles for second place to lose against a Trumpist.
She's earned a lot of goodwill from me with just how strongly she supported Biden and continues to do so (is on his transition team). I find it funny how deadset everyone is against the very idea when we don't even know that much about her actual politics or how much they differ from her husband's. It's pretty clear they very strongly differ from the current GOP's at least.
Besides, we're talking about the Arizona governorship here, which unless you live in Arizona, doesn't affect you that much unlike a Senate seat might. Say she does have some neocon tendencies, so what? Is Arizona gonna nuke Iran? It's good to keep state governments run by sane, sensible people when at all possible, regardless of party even, which is why I think if I personally lived in Arizona, I might support this hypothetical run just because it might be the best chance of stopping an insane, insensible Trumpist from winning.
Also, keep in mind just how close McCain came to caucusing with the Dems back in 2001:
https://www.cnn.com/2018/08/27/politics/tom-daschle-john-mccain-switching-parties/index.htmlHis widow entering politics as a Democrat would hardly be the most shocking thing in the world.