If you look at the general outline for any Digimon season, you can see just how lopsided Zero Two's plot is compared to others. As you said with Adventure, the Chosen had already defeated Devimon and were almost to Etemon's defeat. (I've been listening to several retrospective Digimon podcasts, so Adventure's plot is fresh in my mind, despite not watching it in years.) It's the same for the other seasons.
Tamers: In the Deva arc, and Juggernaut had been used
Frontier: All the beast spirits had been found, and Orphanimon summons the Chosen to the Rose Morning Star
Savers: The three main characters are in the Digital World, preparing to fight Merukimon
Compare those to Zero Two, where the Kaiser isn't defeated for another four episodes (outlasting the previous season's first villain by eight episodes), and then right after that is the rush of several different plot points and enemies. Never mind the interruption during the Kaiser arc with Dagomon and the dark world.
I just think a lot of how the Kaiser arc was plotted out and where it could have been condensed. With my rewrite (still stuck on chapter 2, by the way), I cut the Kaiser arc down from 21 episodes to 12 chapters, equivalent to an episode per chapter.
It's also strange how they keep driving home the Ishida-Takaishi brothers' dynamic. It even came up again in tri, when Meiko talked to Takeru in the bath house. But the writers could have shared different information related to the plot of tri rather than the relationship between two characters that everyone in the audience knows already.
The original version of the scene between Tailmon and Wizarmon actually did make me tear up, especially at the end there. I really hope there's some continuation to that character dynamic in tri, especially since it's such a large part of Tailmon's character and now she's been rebooted.
Thanks for the birthday wishes! :D