Uh for the most part I can agree with your post.

I will just add though, that I think them being so reluctant to integrate multiple systems into a singular piece of content will always be the biggest downfall, e.g., Deep Dungeon is always only going to amount to it's current form. By now it should've at least had essences/lost actions (and I don't necessarily mean that you need to farm them). Just as Island Sanctuary probably never will have something similar to treasure hunts, or sightseeing incorporated into it. The content is just treated and developed far too insularly. They really need to step back a little IMO and ask the question:
"Okay, what content have we developed, and can we incorporate some features from that content into newer content, so that when we inevitably need to 'discontinue' that particular piece of content - People will still be able to experience some of the more pronounced features elsewhere in the game.