Eden Ushinatta wrote: It doesn't matter when the production will start. That's irrelevant. The amount of episodes will remain the same. Even if the production starts 3 months from now, what this means is that the series will be released later, not that the content will change or increase. 6 more chapters is the maximum the manga can reach without the content becoming too much for the anime to handle.
Except the change of pace in the anime with the uprising arc was justified, given how badly the chps were paced in the manga, and any and all world building and character interactions you may had felt were removed for the worst weren't really. Like the "friendship" Levi and that business guy had in the manga didn't amount to anything in the grand scheme of things. He was killed and then totally forgotten about, minus how it led to his son receving some development. Most fans were very wary of how things went with the manga version of the uprising arc, even Isayama admitted he screwed up there. Sure he had the right ideas but the structure in which he executed them was wrong.
I doubt this final arc will be rushed like that tho. They may have to rearrange a couple of things, but even that is unlikely. Also the statement that guy made about 6 more chps being the max the anime can handle is very debatable. Let's not forget we're surely going to get a break in between the season like we did with season 3, which was certaintly a network decision where they just want to give one show a break and give its time slot to another show. TV networks do that all the time.
I strongly disagree with you on the Uprising arc. It was my favorite arc in the manga until these last two arcs, but while the anime adaptation was good, it felt too rushed. Not to mention that multiple scenes of Dimo Reeves were cut. The cuts were done at the expense of character development for him. It's really unfortunate.