mobile CC
mobile solar panel
colonize other planets
artillery units
air units
water units
new weapons
etc...
Sorry ECC, but really?
Mobile CC: Um, what? Convec + CC kit = mobile CC...
Mobile Solar Panel: Again what? Convec + solar panel, not like it requires tube to work or anything, so what is the point of the mobility?
Colonize other planets: Ok, this one I thought of 2. Expanded story line and adds more room and crap. I feel it would add some area to work with.
Artillery Units: Thor's Hammer, Acid Cloud, ESG... hell, even EMP Missile
Air Units: No atmosphere
Water Units: No bodies of water on a planet with no atmosphere
New Weapons: This is very very blunt.
Thou only unit I every wanted added was a train. It kinda seems more practical to use a train to transport goods (from the mine to smelter, or from 1 colony to another) then to get loads of cargo trucks going back and forth....