I gave my initial thoughts here but I thought it worth boiling down to a few features I (possibly selfishly) would like to see:
Lemmy login (and other Threadiverse devices like Mbin/Kbin and perhaps PieFed but the lack of an API may be an issue) - you can already use your login from a number of other Fediverse services.
Import IMDb lists - you can import Letterboxd ones.
As both features are already running in NeoDB (just for other websites) it should lower the bar for these changes, compared with starting from scratch.
So I actually haven't signed into one with my masto account (yet) ... I saw the permissions it was taking and got a little concerned that it was taking write permissions over my account, specifically posts and media ... not knowing enough about it I noped out until I could clarify what's going on.
Do you know what that's about? Naively it seems unnecessary ... but is the idea that I can post on a neoDB instance and have that post appear as though it's from my mastodon account?
I wondered what that did. I wouldn't use it - just follow my neodb account if you want to see that stuff. Same as Bookwyrm - if you want to see what I'm reading, follow that account.
Actually some link between Bookwyrm and NeoDB would be good. I'd rather keep my books on Bookwyrm, but if it could be synced to NeoDB that would be cool.