Well, I was wrong about Savitar being Wally (Keiynan Lonsdale), but at least I was in the ballpark of "speedster close to the team who comes from the future"? That counts for something, right?
Okay, it doesn't count for all that much, but when I posited that Savitar was Wally, a lot of what I ended up describing could've accounted for From the Future and Scarred Barry Allen (Grant Gustin): paranoia in a post-Flashpoint existence, someone close to the team, and a suit of armor that taps into the Speed Force. I just got the "who" wrong. We'll have to wait (hopefully just) a week for the "what" that drove this Barry Allen to go all dark side, but I don't know that his motivations will ultimately mean a whole lot, either.
Wells/Thawne (Tom Cavanagh) and Zoom (Teddy Sears), after all, did all their damage not because of their master plans but because of what the reveal of their identities did to Team Flash. They undermined confidences, they created senses of betrayal and of being little more than pawns. They were actors in a scheme that, ultimately, afforded them no actual agency since everything they did went exactly as Thawne and Zoom had planned all along (just what they planned was never super-interesting).
And Savitar being a Barry Allen will certainly do a lot of that and then some to Team Flash, particularly our Barry Allen (Grant Gustin). While every season has mostly been about Barry coming to accept the emotional tolls of his life and believing in himself, that he is fast enough, this season ended up being about that almost entirely. Since his resetting of Flashpoint, Barry has been dealing with alien invasions, giving powers to people who didn't want them, changing the gender of babies in Star City, and questioning the nature of his heroism if he couldn't stop Grodd without killing him. This was all on top of trying to figure out a way to stop Savitar from killing Iris (Candice Patton).
In no small way, Barry's always been his own worst enemy, and even more so this season. Indeed, it's actually incredibly fitting that Savitar turned out to be Barry Allen since Barry has been the season's big bad all along, and I don't that just say because Savitar's been creeping around all season. I mean that thanks to creating and then undoing Flashpoint, Barry set all those dominoes toppling for this season's havoc. This is all on him in a way that "not being fast enough" isn't.
When superheroes encounter evil versions of themselves, it's normally as a way of facing the darker/est parts of themselves and emerging better and wiser. Barry has been screwing up all season on his own, without that evil version of himself to really do much of anything. This is why, ultimately, Future Barry's reasons probably won't matter. As Abra Kadabra (David Dastmalchian) noted, no one hurt Flash like Savitar did, and no one punishes himself more for not being better than he is than Barry Allen does.
Where this places Savitar in the rankings of Thawne and Zoom, I can't say yet (but probably higher than Zoom because Zoom was just terribly boring). A lot of this hinges, for me anyway, on how the rest of this season (and then some of next) plays out, and how Barry changes as a result. Barry has always looked to the past or to future to remedying his woes, but he's never looked at how he can change in the present. Much like his jaunt to the future last week and the many effects of Flashpoint, hopefully facing a literal future self will spur Barry to look at himself and the world itself in the here and now when it comes to solving his problems.