It can come off as misogynistic but I get what you are saying. I also agree, generally you want someone very loyal to your cause. Especially if you are fairly old.
I do doubt her Left-Wing cred a bit, or compared to Bernie she isn't all there on a few things. But she is further Left than clearly many party goons want since she is never floated on their list of who they'd ratfuck it for. She is just enough not in Sanders camp that really I don't think she'd make a good partner.
This is also why I doubt AOC as a choice. Bless her, but even on the campaign trail she often forgets to even mention who she is campaigning for.
That is why I kinda settle on Nina Turner or Tulsi Gabbard; I can't think of anyone else who has suffered for Bernie's sake, who've shown that level of loyalty. Both have paid a huge price for their loyalty so I'd pick either one. While obviously I'm biased for Gabbard for her Hinduism; the objective part of me would say Turner is a safe choice because she is from Ohio and is well known there and right now IDK what Gabbards political goals are long term, I kinda think she is on her own quest now or already has some other arrangement with Sanders.
Warren is a more useful Senator strategically; but she will have to win back favor with the Left after some of her stunts this campaign. She has made a lot of mistakes. But not fatal mistakes.