I think there's a lot more to Sanders's defeat last time than DNC fuckery. They had a clear favorite and they put their thumbs on the scale for her, but they're not all-powerful; there were plenty of other problems that led to his defeat, from systemic (closed primaries) to local (polling places unable to accommodate demand) to Bernie's own campaign (he never quite managed to appeal to minority voters, outside of the youth vote) to the sheer size of the Clinton machine. All that and he still did better than anyone expected. He's got an uphill battle ahead of him this time, and the DNC's not going to help, but I wouldn't count him out yet either.
Another problem is the recent changes to the superdelegate system: the superdelegates have less influence on first ballot than they used to, but greater influence on second ballot. It's entirely possible that this won't matter, that this huge field will be winnowed down to two candidates within the first few primaries and one of them will win an outright majority on the first ballot. But it's
also possible that, with a field this size, nobody will get a majority, and then the superdelegates pick.
If the primary were tomorrow...well, leaving aside that I'd be SOL because I haven't changed my registration to D so I can vote in the primary yet, if the primary were tomorrow I think I'd take Warren over Sanders. I'm more simpatico with Sanders's view that capitalism is the problem than Warren's belief that we can fix capitalism with proper oversight and regulation, but in terms of what a president can practically accomplish in eight years, I don't think those two beliefs will result in substantially different policy outcomes. I really like some of the policy proposals Warren has put out there, like the wealth tax. (Though maybe that's a good argument that we're better off keeping her in the senate.)
On the other hand, her claim of native heritage, and her subsequent handling of the scandal, have not impressed me, and some of her recent statements have concerned me too. While I agree with her proposal to break up big tech, the arguments she makes in her
Medium article don't impress me (you're going to try and make a case for breaking up Amazon and you're going to go with "they have their own store brand" and not even mention AWS?). Plus she's made some recent remarks on copyright where she used some key phrases that sound like
MPAA/RIAA talking points, and nope I definitely don't think the solution to the tech cartel problem can be found by getting advice from the media cartels.
All that said...this is very probably a moot point, for reasons stated upthread: the primary
isn't tomorrow, it's a year from now, and I find it unlikely that I'll have to choose between Warren and Sanders. They're largely competing for the same voters, and I think it's likely that one of them will take a clear and early lead over the other (probably Sanders over Warren, for the reasons you mention). If they're both still in contention by this time next year, I'll back whichever one of them stands a better chance of getting the nomination. If they're both knocked out early, well, Gillibrand would be my next choice but I don't expect her to outlast the both of them. (And I like everything I've heard about Buttigieg, but I'd be
very surprised if he became a major contender.) If it really is looking like Biden/Harris/O'Rourke/Booker or similar, well, I'll cross that bridge when I come to it. I don't like Harris on criminal justice, I don't like Booker on education or healthcare, and I don't like Biden or O'Rourke on a
lot of stuff, but if all the progressive candidates get knocked out early, I guess I'll figure out which of the remaining candidates I dislike least.
Of course, there's one more vexing fact that makes the entire primary season frustrating, and that's that the winner of the Iowa caucus has gone on to win the Democratic nominee in every election since I've been old enough to vote*. It's entirely possible that that happens again, that one candidate takes an early lead, the narrative snowballs, and that early lead becomes self-reinforcing. I think that, with a field this size, we're
probably looking at a more volatile scenario than that, and Iowa's influence may be diminished this time -- but there's really no way of knowing until we get there.
...which is a giant wall of text to say that basically I've got preferences right now but they probably won't make much difference by the time I actually vote. Which is why I haven't talked much about the primaries up to this point. I've got a lot to say, but I recognize that what I think a year before the primary is probably going to bear very little resemblance to my decision once people actually start voting.
* I didn't vote in the 2000 primary but I found out later that I could have. I was only 17 at the time of the primary, but it turns out that in Arizona, if you're 18 by the general election, you can vote in the primary.