Rationale for 2D world in which planets don't move

[dmm]

Greghacke's comment makes great sense when comparing distances between inner planets like Earth and outer planets like Neptune. The distance between them doesn't depend much on their orbital positions because the inner planets are so close to Sol while the outer planets are so far away. But for comparing inner to inner, or outer to outer, the orbital positions will make a big difference.

However, I just thought of another argument that strengthens Greghacke's point. It is this: the orbital periods of the outer planets are quite large, so over the course of 100 years (=1000 game turns) maybe their relative distances wouldn't change that much. If so, that just leaves the problem of inner-to-inner distances. Since those are relatively small, you'd only change them by maybe one sector and so it isn't worth keeping track of. The extra realism would not affect game play much.

There's one big hole in the idea, though. It still doesn't explain minefields. Why can't ships avoid them simply by going out of the ecliptic (the plane containing the planetary orbits)?