You just explained gamedev. It takes a lot of time, but the effort is worth it (sometimes).
We don’t know what it is lacking now because we don’t have a roadmap of what it needs before release.
It was already like that in EA v1. This game was literally a mix of recycled content straight up imported from CI4 and CI5. This short while lasts 18 months and we only got 4 new bosses (6 if we count meme egg canon version and another multiplicity as new boss).
Define “then”. It’s 18 months since EA v1. I know that programming is time consuming, but how is it different if you spend it on adding another recycled content from spending it on making a new one? The second option at least makes the game fresh, more exciting. Really, we have enough boss mixes for now.
Yeah, it doesn’t sound bad unless you remember that CIU is a rather specific game from technical point of view. Here IA explained it well:
About moderation and development - #18 by InterAction_studios
So I wouldn’t be surprised if making few small changes in the AI takes much longer than it should have.