I think the way federation currently works spells doom for the fediverse, should any service of it get major traction. Currently, if you subscribe to a community on Lemmy or follow a user on Mastodon, your instance will pull the content of that instance/user and make it available for all to see and interact with. What seems like a good idea to spread content however is becomming the achilles heel of the fediverse: The admins of Lemmy/Mastodon instances are liable in many juristictions for the content their servers are distributing. This means in practice that many Lemmy/Mastodon instances block NSFW content for example, as the admins, understandably so, are either unwilling or incapable of making sure they are not running afoul of any laws.
As such, I think that the fediverse needs to offer a way for users to follow content from other instances without having that content be stored, let alone shared by their home instances.
A question I have at this point is where this criticism is best levied against. Is it the job of Lemmy/Mastodon to provide such a form of federation, or does the ActivityPub protocol needs to be ammended?
There is no perfect solution, though. Both Reddit and Lemmy have inherent flaws and benefits because they serve different purposes.
There is no perfect solution, but having the core feature, federation itself, work to the detriment of the admins that run the instances, is completely antithetical to what federation is meant to achieve: A decentralized network.