Perhaps, adding a Orbital Defence type structure, that gives you a defensive value to counter act strafing/close air support runs from smaller (Fac or Fighter, perhaps small frigates.) vessels. This enables conventional ground attack/artillery/support, adds more depth for defending and attacking with ground forces, and the orbital defence platforms/structures could also do damage to troop transports/assault dropships when the troops initially land.
One small problem is that the only weapons that work in Atmosphere are Meson, and missiles? ((I can't remember if railguns can but I know Gauss can't) so perhaps you'd have to loosen the rules in that respect to make it viable for Gauss/Railgun/Laser armed fighters, to do strafing runs, or Facs/small frigates doing the same thing.
Sorry if the grammar/spelling of this post is horrific, i'm pretty tired as I'm writing this >.>. I'll come back and edit it when I have some brain capacity back; until then i'll let you all decipher it.