Sure. It boils down to “should I have the ability to moderate posts on a followed comm”. In the event of a rule conflict (removal, pin thread, etc) , which mod team gets to make the decision about which set of rules to follow? If you say “it’s up to each mod team to decide.”, then that would really be no different than crossposting which already exists in Lemmy, and each comm will then have different content anyways.
Let me put it this way, using a reddit analogy: do you think it would be a useful feature for r/gaming to follow r/games and r/truegaming on a subreddit level to centralize all gaming content on reddit?