I like some depth, but mostly in the name of variety. So, how deep is "depth" - I prefer just going a couple levels deep, stop before it gets very nerdy ;) I prefer cross pack functionality over depth, I guess.
I also see there are a few depth features that will affect my game badly, even when I don't really use those features. One example is the milestone system which is the main reason why I skip the Growing Together pack. I have 500+ sims, and all that info added to most of them will most likely affect my game performance negatively. If I played just 1 household, it would be interesting. But this system is also a good example of something that got way too detailed. Who needs to look back to check whether they as infant tasted apple or orange first? Or if they learned to move before they learned to burp? I mean, all those details are totally not interesting as milestones to get saved for your lifetime. If the system only saved the latest 10 milestones, it would be better. Or if milestones were actually huge things and not those everyday-things that everybody will get. Not meaning to criticize the pack, just saying that some times details get out of hand...
A detail I have been hoping for since 2014 is individual cash accounts. Good for a household of individualists, or to have kids/teens save up.
This late in the series, I'm not sure that depth is needed, because most of us have our ways to play anyway, some of us even with quite old saves. So, in this aspect I prefer variety, which means new features and content that can be used regardless of world or house played. General goodies that might not be totally general, but neither too special and deep.