The only issue of any substance is that I often like to browse a particular community. It would be nice to get some front-end interface solution that makes it reasonable to do so for multiple communities. I’m happy to set it up manually once, but it would be tedious to check in on, say, the mechanical keyboard communities on 5 different instances every day.
For my main feed, a shotgun approach is absolutely fine, and I wouldn’t want to weaken the benefits of federation by herding everyone into a single instance per “interest.”
I do think that maybe the Lemmy developers were expecting each instance to have a more distinct character than is happening so far, at least on average. Federation in the threadiverse seems to be acting more like simple distribution, load balancing, and decentralization, rather than digital tourism defaulting to open borders.