It would be great to have some way to give some more weight to small communities. At the moment my solution is to browse the communities separately although I definitely would prefer a "front page" with a variety of stuff..
Maybe add a weight to each community based on its activity relative to the user's other subscriptions, and use that when creating the feed. I really need to dive into the codebase..
I think it should be like this. Look at the number of community members and the upvote rate they received. For example, if there are 100 people in a community and they get 10 upvotes, they should get ahead of 90 upvotes in a community of a thousand people.