The new UI is just great. It’s really refreshing, even though I think I’ll actually miss the old interface - but that’s just silly nostalgia. 
One thing it seems to help with is the privileged extension interoperability:
I guess those notifications will show up in the “Updates” tab? I was confused by that tab at first - I thought proposed updates would show up there, but it seems like it’s more “Updates performed” and the upcoming updates are in the first tab.
I actually liked the distinction in the old app between “Recently updated” and “New apps”… It looks like the new apps show up first in the list, but it would be nice to not lose that feature: I really like to review the latest entries in F-Droid…
Anyways, this is a great change, I welcome it with open arms and congratulate the F-Droid team on such a bold move. I hope it goes well for everyone and gets the great reception it desserves!