Having just watched it last night, I had the same gripe as you did regarding the titan changes coming undone, but now I think it kinda works well with the shift in tone we get when it's revealed that despite the events that took place, the cycle is doomed to continue.

There's a real sense of optimism after the fight that I think is actually pretty important to one of AoT's messages about how even if we're trapped in these awful cycles, there are moments within those cycles where things can be good and worth living for.