I don't know if I would go so far as to say that I want them to be actual units but I do want them to have more importance. Perhaps something similiar to air units only general controls. If you launch a Recon satellite you could task it to only look at a specific enemy for your current war.
Recon satellite - name implies what it does
Economy Satellite - No control over this it would just boost the economy slightly to signify cell phones and such and how it creates a new market
Military Satellite - First remove the SDI wonder, instead have multiple military satellite that can shoot down missiles and you pick the area they protect. The more of these in one area the more likely they are to shoot down missiles.
Attack Satellite - For one of the last techs you should get some sort of military weapon born from a satellite. Laser weapon perhaps, nuke launcher from space thereby negating your military sats, etc.
Recon satellite - name implies what it does
Economy Satellite - No control over this it would just boost the economy slightly to signify cell phones and such and how it creates a new market
Military Satellite - First remove the SDI wonder, instead have multiple military satellite that can shoot down missiles and you pick the area they protect. The more of these in one area the more likely they are to shoot down missiles.
Attack Satellite - For one of the last techs you should get some sort of military weapon born from a satellite. Laser weapon perhaps, nuke launcher from space thereby negating your military sats, etc.