It's time to answer the OP, now that the debates are over.
Is starting third party and ending third party "changing my mind" this year? I suppose not.
Last decade this forum railed heavily against George W. Bush, and it was much deserved. That argument was won by my opponents, IMO. Naturally partisanship stopped me from seeing it for a few years, until someone from my side of the fence made a compelling argument in 2006. See, we draw lines, setup barriers and stereotypes, but when an argument transcends political sports teams... that is when it has an impact. Helps people realize there's more to it than Red Team and Blue Team.
I saw those same Neocon policies I despised in the Republican 2008, and 2012 candidates. Warmongering to depose our civil liberties is not my cup of tea.
This year, those same folks railed against Donald Trump. If the enemy of my enemy is a friend... I gave him the benefit of the doubt, as unusual and hated by the establishment as he was. This was reinforced by the relentless tide of faux attacks against him, either exaggerations, misrepresentations, or flat out lies. The smear campaign doubled down on the notion that this is a guy to rock the boat, an action sorely needed when the elections I've seen have contained little more than... baskets of deplorable for candidates.
When the first debate happened it became pretty clear what I had seen. Trump is a babbling buffoon on a short script. He has never spoken in substance on an issue that he did not rehearse, and that's a short list. Lately he's employed GOP dog whistles on guns, abortions, trickle down... he doesn't know how to debate. He doesn't know how to sway people, and this reinforces one of my positions that governors are better suited to be President. Moreover, Trump is ego centric... some of his rhetoric is both for and against Neocon positions... but overall he comes across as a dangerous big-gov dictator type. Unstable and on a short fuse. A very stupid person.
He's also proven to be a liar, IMO, by promising everything to everyone. Even when they are contradictory. I mean, we know... I could just go on, but there are strong substantive reasons Donald Trump should not be President. Sitting down to and listening to him in the debates, painful as that was, made it perfectly clear. So I moved from neutral to opposed.
But wait, I haven't said who I am for! Well it's quite difficult to be "for" anyone in this election. Bernie Sanders seemed to be the best, not corrupted and with mixed positions. A low bar, perhaps, but miles above the rest. I still stand by the idea that if he was on the ballot he'd have my vote. Neither third party is perfect, but I might believe in a number of things closer to Jill Stein.
I have never, and will never, vote for Donald Trump.