I like this part of lemmy. You can easily toggle whether you want posts/communities from your instance or globally. And I agree that some of the communities are redundant but I've found that it is easy enough to follow similar communities so my feed is all content I like.

I view it as a benefit because it encourages a small world, tribal model which works better with human brains.

It's definitely different however, so I can see some friction if it's not what people are used to. Frankly I don't want one topic with thousands of comments, most of which won't get read.

I think one needs to transition away from the dopamine fueled high and focus more on what brings meaningful discussion and sharing of diverse opinions. With that said, I wouldn't be opposed to a feature that allows users to quickly jump to the same discussion on other instances or communities.