I forgot some stuff:
Huge planets should always have several Tiny planets nearby. These would represent very large moons like Titan.
Making None atmospheres common (in order to be more realistic) would mean a big advantage for None "breathers." So to compensate you'd have to make sizeable None planets extremely rare, which is probably realistic anyway. (That would make None races very interesting to play. Lots of room for expansion in every system, but lots of planets to defend.)
If planets had temperatures, these would generally get more frigid the further away planets were from their star.
And while I'm talking about realism: what's up with having two (or three!) main sequence stars close together, at the center of a star system, surrounded by planets?
