Its been bothering me too, that the large communities have been swamping out smaller ones.
As one solution, the closed PR linked in this issue has some more context, but we plan to add a Best sort, that retains the qualities of hot, but gives a boost for small communities over larger ones. This shouldn't be too difficult to add, as its very similar to hot.
Another benefit of lemmy being FOSS, is that we have the option to add many more sorts as time goes on.
Any concerns about duplicate communities across multiple instances?