People have begged for space-sims for years now, and it just occurred to me that while LL may not consider them feasible, a potential compromise could be considered. Namely, set aside a group of servers to provide sims with a moon-like environment, moon textures, lowered gravity, separate from the main grid, but accessible via clicking on the moon. Use the map interface to generate a moon image for the main grid based on the moon sims and do the same thing to generate an 'earth' image for the moon sims.
I believe this would allow for growth in an original direction without continuing to explode the size of the main grid as presented on the map, sorta like the northern continent once allowed for expansion without growing the mainland (though it did eventually start to balloon).