I haven't quite finished the event yet, but I've enjoyed what I've played so far, story-wise. I love that it did actually customize our party while we were on the walk. Made it feel surprisingly immersive.
I found the story and event theme uninteresting, and the games middling, overall I found it disappointing for a flagship event. Fontaine feels like a step back in terms of event quality to me so far.
I did like the change in party that you mentioned, it gave me a chance to play around with Xiao for a bit which was nice. And it was generally enjoyable to have a reason to go take a walk in Liyue.
Yeah, I agree that both of those have gotten a lot better this region. But the exploration content quantity has also seemingly shrunk down unless I‘ve become a lot faster at exploring.
It really might just feel that way because unlike Sumeru Fontaine has not locked majority of the exploration behind a quest like the Aranara or Jeht one.
As much as I like Sumeru, having those big exploration parts locked behind huges quests wasn't something I liked much, especially with the Aranara one which I found incredibly hard to follow due to so many similar names on top of the fantasy words.