My main usage case of Reddit was for the more niche communities by and large, so I can definitely appreciate that.

It's the case at the moment where the "popular" communities feel niche, or at least similar to how they did when I first started Reddit back in 2012, and unfortunately the formerly niche Reddit communities are essentially non-existent here. I view this as an issue that will be fixed with time though, should Lemmy continue growing of course, so I don't really have a complaint about that for the moment.

My main issue is that it doesn't all come under one big "Lemmy" umbrella. Different instances have different rules and different accounts by definition of a federated space. I just think things are better managed if the site aligns with a single goal and singular ruleset, rather than having loads of little separate ones. I acknowledge this is entirely personal taste, I have no desire to force my viewpoint, it's just how I feel about it.

Defederation is also a big issue. There's lots of claims that federating the site prevents the next Spez for example. In my view, it really just opens up the possibility of a lot of micro-spezs. There's theoretically nothing stopping the guy who runs lemmy.world from pulling the plug tomorrow, leaving myself and whoever is left to try and pick up the pieces. This is true of any instance and the accounts and communities contained by said instance. Even if it's not quite as drastic as pulling the plug, they could certainly pull my access from here, which would be rather frustrating.

Again, I do believe it ultimately comes down to personal preference. I think I'm just more willing to put trust behind a larger entity than a bunch of smaller ones.