I watched Franxx as it was airing and honestly I think everyone was just hoping for le epin Gainax twist to make it eventually be not shit. It was one of the worst anime that I've ever actually had an expectation for. Everyone kept just waiting for it to improve and it never did, and the plot twists other than Zero Two being part dinosaur were pretty predictable. The robot designs weren't boilerplate but they weren't all that interesting other than the main robot, and the faces really were dumb on them.
Shitposting on /a/ when fatboy and ichigo got cucked was the most fun there was to find in that show. The setting was silly, the premise was out there even for an anime, and the climatic battle was a disappointment.
Speaking as someone who watched it while it was airing, I was mainly just disappointed that the ending dropped the ball. That said, there were still moments spread throughout the second half of the series, mainly involving Hiro and Zero Two, that still made it tolerable to watch, at least imo.
Personally, the "big twist" I wanted was a bigger exploration of their messed up society, which was only really hinted at in the one episode where one of the kids got outside, and the possibility of rebellion arc using the theme of child rebelling against parent. Felt like that was what they were setting up, but then they pulled off the Gainax twist of lol aliens.
Yeah, the main problem I have with the whole VIRM alien reveal is that they have very little to do, personally, with the main characters. They are literally thrust into the plot with very little build up aside from a few hints here and there, and they don't have any personal ties with Hiro and Zero Two's plight. If they were going to be introduced, they needed more build up and foreshadowing, alongside a deeper connection with the heroes.
It points to the second half being rushed, and if the rumors about the staff not being given the time they needed and wanted in order to plan said half out are true, it wouldn't surprise me in the slightest.
What if it retconned the ending?
You have to remember Evangelion’s ending was also rushed and shitty, with Ep 25 being a short timeskip starting with an intro narration along the lines of “everyone fucking died and Instrumentality happened”. The difference is they were pretty upfront about it and announced that they were going to do a “real” ending with actual budget that would be out a year after the show aired.
If Franxx had, say, a movie or second season that straight up ignored the last x episodes, do you think that would work to interest people who felt burned by the ending?
Granted, Evangelion's OG ending wasn't nearly as out of left-field as Franxx's, and had more reasons that excuse it, but I agree.
Honestly, given how many people online are still asking for a continuation of the series, alongside it still being fairly popular in Japan, I think it would interest several who thought it deserved a better climax. Heck, if they did something similar to how the manga redid the second half, that would also work very well, as it was praised for giving a much more satisfying conclusion.
Personally, I would have them either do that, or follow the ending of Hiro and Zero Two being reincarnated, and have them regain their memories while traveling the world, alongside giving them a more personal connection with VIRM so as to make the alien villains feel less out of place.