(6.2 spoilers, duh)
Back in Asphodelos, we were given a slower but steadier storyline that set up things but didn't try to get too far ahead of itself. The Abyssos storyline on the other hand, seems to me like it took the Pandaemonium story and rushed it to a conclusion. Yes, I know that the story isn't actually done yet, but it feels like we have accomplished everything that we set out to do, and that the third tier is just going to be figuring out why Pandaemonium is in the aetherial sea)
Asphodelos gave us one area of Pandemonium to explore and took the time to set up things and characters properly. Erichinthos, Themis, and even Hesperos all felt like actual characters in the Asphodelos storyline. Meanwhile, while Abyssos did reintroduce Lahabrea and his other half well enough, it feels like every other new character wasn't really given the proper time they needed. Hegemone literally is just not a character, Agdistis could be any other random NPC and it would change nothing about her, and Athena has the motivation of 'because I wanted to'. While in Athena's case, it is very possible that they reveal her motivation in the third act, I doubt the other two will be receiving that treatment, especially seeing that Agdistis is now dead. Does every character need to have their own cutscene explaining their deepest darkest motivations? No, but at least Hesperos was given the time to have a basic character set up.
But let's say that there was proper character development. The story and raids themselves are still rushed. Asphodelos had four entire raids take place in it, while Abyssos has share its screentime with Tartaros. Asphodelos built up to Hesperos, with said keyward being a major threat we needed to defeat. In Abyssos, we defeat not one, but TWO keywards consecutively, and neither are the last boss or treated as a big threat to be built up to, they just get introduced as the next thing to kill, which we proceed to just do.
I do like the gameplay aspect of each raid, (personally my favorite is P6, which ironically I believe has the worst story in Abyssos behind it) but after going through Asphodelos, I just don't think this part of the raid series should have been this early on. Abyssos itself seems more like an act 3 finale than the middle chapter which is what it should have been. I don't have major issues with the direction the story went, but I think that if the Abyssos story was split up between Abyssos and a third raid tier, (Tartaros) the story would have the time to set up the things it wanted to.