Solving the groups problem would be a game changer. I can't recreate the same kind of group value that Facebook Groups provides or Google Groups provided anywhere else.

Maybe it's impossible, but hopefully some day we can get to a point where social media silos are not necessary, with easy to set up and use personal sites/apps that use Indieweb principles. The Indieweb movement is excellent for this but needs a lot more developer contributions to make this dent a reality.