About #1 (merging communities): to a certain extent users already do this. Nothing stops you from locking [!pancakes@a.com](/c/pancakes@a.com) with a pinned thread like "go to [!pancakes@b.com](/c/pancakes@b.com)".

If you aren't already the moderator of n-1 communities on a multitude of instances, there are some pretty significant challenges:

• Find all the communities on a given topic (easy)
• Convince people that consolidation is a good idea (difficult)
• Get people, many of whom are reluctant to see a community on their home instance locked, to decide on a which community to switch to (sometimes impossible)
• Contact the moderators (or the admins, if the mods are inactive) of each of the n-1 communities and get them to lock each community, with appropriate links to the decided upon community (tedious)

It's a right pain-in-the-ass to do properly, and I've had many more failures than I've had successes.