I think the problem I've noticed with Lemmy is I tend to only get the more popular communities showing up over and over again. Reddit was at least a little better about showing smaller subreddits I visited in my main feed at least somewhat often. Not sure if I just need to change how I sort on Lemmy, I currently use hot and subscribed.

The code is open source, so you can inspect it yourself.

I doubt there's much incentive for Devs to implement features that would make Lemmy more facebook-like. There's no profit motive for it, and there are lots of other features and bug fixes that deserve their attention.

The good thing is lemmy is so new that even if the devs wanted to, they probably haven't had the time (or data) to implement any of this.