Worm is a lot more regularly intense than Ward is; Taylor is the queen of escalation and the narrative reflects that, never really giving her (or the reader) time to breathe. Meanwhile Ward's protagonist actively tries to take time off, de-escalate, be mindful, and it does affect the pacing. There's slightly fewer action scenes, but they're just as good, if not better in some cases.
As far as I remember, Dragon shows up a few times but isn't as important as in Worm. Panacea does appear, with a pretty important, controversial, and spoileriffic role in the story.
The Endbringers don't come back in for a while, but they do show up and they do end up being pretty important. If you enjoyed Leviathan's and Behemoth's fights, you will absolutely adore pretty much the entire back half of Ward's action.
Ward's side characters also shine a lot more than Worm's, in my opinion, and I think it's because the author just had more experience writing by the time he did Ward. Rain is probably my favorite protagonist cape in the series, for example.
I'm not sure on audiobooks, I read Ward as it was being written, starting when it was in like chapter 6 or 7. I don't think the first audiobook was finished for months after the end.
I wouldn't call Ward slice-of-life, necessarily, but there are a few parts I can think of off-hand like a little shopping trip, some therapy, etc that Taylor would never have had time for in Worm. These go away as the story progresses, but they're nice, and a good look into how the protagonists are feeling and dealing with the situation.
Less Dragon is a bit of a bummer, but hopefully the myriad of new capes ends up balancing that for you.
As for Wildbow's other works, I haven't had the time to focus on reading any (thanks life), but I know a lot of people think Pact and Pale are his best works, so I am excited to get into those someday. If I remember right, pact and twig have little cameos in Ward, like TV shows or books or something, and Worm has similar cameos in those works too.
The hopes for a trilogy are probably not gonna happen unfortunately, he's said that he's pretty tired of the genre and how some parts of the fandom reacted to Ward's style and story direction. Tbh I'm not sure what a third entry would even look like, but I said that before I knew about Ward too, so who knows!