So many theories
At this point I don't care anymore. I just need the show to protect Iris and the WA love story. From my PoV this reveal could destroy them beyond repair. They need to be careful here because I completely disagree that since Iris won't die and SaviBarry won't come to pass the whole thing would be meaningless. They've spent a season on this and it will remain attached to the ship forever. Iris "sabotaging" Linda is still used as a reason to hate on her so I don't even want to think about what would happen if SaviBarry murdered Iris just because...
I don't know if Killer Frost sticks but if she uses the powers to do good it's still a change. She started the season with powers that scared her and then learned how to take control. I actually think Killer Frost will be a villain even after the finale. She can be the non speedster big bad for the first half of S4. I just don't think we're done with her just yet.
Barry and Iris was established before this season but S3 has them engaged and living together in that nice apartment of theirs. This season has been about all but "Barry and Iris are destined to be together". It's actually the opposite. The arc has been about the characters defying their own destiny. Even though the execution has been sloppy I'm weirdly grateful that the writers have given them this storyline. This is how Barry and Iris act when they learn about a future that they do NOT want. There's a stark difference between Iris learning that her days are numbered and Iris learning that she marries Barry in the future/Earth-2. Scared vs intrigued and hopeful. This may not convince the WA detractors that Iris is with Barry because she loves him and not because destiny says so but whatever
Wally and Jesse don't have now the same relationship they had in S2. Whether they stay together or break up, it's still a change.
Joe and Cecile is new. Agree. Joe even took off his wedding ring for her. I think this is huge.
I doubt Julian dies but he could go back to London. Or he can keep fighting for Caitlin's soul if she stays Killer Frost past S3.
Wally has speedster powers now. Change that will stick.
I'm not discussing the execution here, just the story. To some/many the writing can be awful but it still doesn't change the fact that powers-wise and relationships-wise the characters are not in the same place they were at the end of S2/beginning of S3.
I agree that they need to change the formula though. While the characters have new powers/new relationship/are at a different stage in their relationships or all of the above they still don't have individual arcs and very little agency. This is what happens when shows are extremely plot-driven. I think that even if they wanted to be done with STAR Labs, their hands are tied. That set is too expensive to get rid of.