Provide the ability for users to migrate their account and all associated data (posts, comments, moderation actions, saved posts, etc.) from one Lemmy instance to another.

To implement this feature you’d either have to:

• Edit the DB entries of every instance to match the new profile;
• Create copies of the old content on the new instance and federate that out, thus duplicating all the data. You could have it delete the old content, but you’d still need to recreate all the posts and comments.

Either of these would be very susceptible to abuse. Giving bad actors a button to force instances to run hundreds, potentially thousands, of operations probably isn’t the best of ideas.