Here's another: "never vote for someone who claims to be omniscient and basically know everything". How about this: "Never vote for someone who claims to never need advice from others". I support "never vote for someone who claims to have all their decisions dictated to them by God".
There are all sorts of extremely low bars that can and should be set. We can easily find tons of people who pass them. Anyone who doesn't pass very basic requirements like this should indeed be disqualified.
To be clear, if Hillary came out and said, "I never meant to say I was beyond bias or that the time and money from my supporters has no influence at all. I'm human. But I meant that there's no quid pro quo. I'm not specifically going to do whatever Wall Street asks, I'm going to do research and listen to other views as well when making decisions," then I would immediately say "okay, she retracted / qualified her previous claims, so she passes that minimum test of acknowledging one's own bias after all".
Currently, she seems to be saying, "oh, I got millions from financiers and gave lots of speeches to Wall Street, but that doesn't influence my views at all". That disqualifies her. Nobody should support anyone who claims such bullshit.
(It's even arguable that Clinton hasn't; she doesn't claim immunity to all bias, she just claims that receiving millions of dollars from the titans of the financial industry somehow doesn't bias her.)
"I will never vote for a person who supports general warrants"
I can apply that to the candidates, and it's extremely helpful in filtering out the really bad ones. That one issue - being in favor of general warrants - is more than enough to disqualify a candidate as being worthy of the presidency.
As with any filter and context, it depends on what filter you choose to you apply, and sometimes how many filters.
When people mistakenly believe that they have to vote for one of the few options given to them, candidates only need to seem decent enough to possibly edge out the others. As different people value different priorities, this inevitably results in a race to the bottom. The only winning move is to not play.
I won't be fooled into thinking that steering the 5% of difference between candidates is worth endorsing the common 95% that is never up for discussion.
There are plenty of people I've voted for, even though I don't think they have great character and/or have done shady things in the past and/or have shown poor judgement on some issues.
For instance, my present city council member has had an extramarital affair with one of his staffers, but OTOH he's something of a visionary as far as city planning goes. I would vote for him again, despite the fact that his actions were deplorable.
Aside: my views on this used to be closer to yours. As years went by I became convinced that withholding my vote was not sending any message (in a Turing sense, principled apathy looks a lot like mere apathy, and may indeed lead to it). Witnessing some very, very close elections was also a factor.