It looks very interesting. What's the default content like? Looking at the SQL in the repository, doesn't seem like there's that much quests provided?
A sibling commenter quipped about which quests are bugged and which aren't, but the reality of it is that the vast majority of quests work perfectly fine, including the quests that are heavily scripted (such as the Battle for the Undercity)
The question is more what's bugged and what's not
The largest issue I can think of that actually impacts overall gameplay is the thread system [0]. It definitely works, but currently threat at times isn't given or reduced in the correct amounts. The most common way this manifests is Growl from Hunter pets not properly taking aggression away
[0] - https://github.com/azerothcore/azerothcore-wotlk/issues/5985