Cookies.
Like I've said elsewhere... the only useful and productive fix for planets at this point is to go back to cookie planets instead of dodecahedrons. The experiment didn't work out, as predicted.
I agree. Planets don't need to be Minecraft big (32k on a side), but we need a continent that is more than 200 blocks on a side on average, to be able to build anything worthy of being called a planet-based structure. The devs think they can improve and optimize dodecahedron planets, but can they make the minimum average side of a continent about 400 blocks? That is probably asking too much.
Meanwhile, cookie planets can easily be that wide, and can be optimized to be thicker, so that you can have a nice, large underground complex, or deep mining.
For anyone who wants to try out cookie planets in the new game, you might still be able to make the following cookie planet templates work.
City Planet
Salvaged Purple Vine Planet
Pyro Industries Planet Plate 1