Dropping asteroids from orbit would be pretty destructive... can't we do that? =P
that is actualy a very good idea....
make a ship which is able to haul asteroids from asteroid rings.
once collected it can jump to an enemy planet and launch it
pretty destructive for the infrastructure and leaves a big hole

however.... this should be some sort of ultimate ship, since it takes out 40% of a planet in 1 hit.... (asteroids look pretty large 2 me in the game.... like the size of a big.. big moon.
i always believed that a space game like sins of a solar empire should have some kind of planetkiller like the deadstar in star wars or the stellar converter in master of orion 2, that would make the game verry real. What i also like are the orbital weapon platforms great work guys.
yeah i rly love the orbital weaopon platforms, even so i think they oversized em..... make alot of satelite turrets which die pretty fast, instead of 1/3 big rocket/mass driver turrets