Well, SMAC's tend to kill things. Fast. Really fast. And they have massive range. How fast? One ship every five seconds. So even 1 SMAC can do a lot of pain. Add in multiple SMAC's, plus some ships for defense and you have Reach not falling, especially as SMAC's will repair ships and host strikecraft, and the Covenant can't send down teams to take out the SMAC's planet-side generators. So Reach having a butt-load of SMAC's will force the Covenant to think more than twice about attacking.This mod will be an example of what happens when an unstoppable object (Covenant) meet an immovable object (UNSC). UNSC are THE faction for turtlers, and Covenant are THE offensive faction, needing only 1 ship for the UNSC's 3.
Just thought I'd correct you, the SMAC's wont be housing strike craft, nor will they be repairing anything. That was decided a while ago, actually. But besides that, a dedicated Covenant assault would steamroll UNSC defenses, I mean a SMAC platform would go down just as quickly as any other UNSC ship. So if the covies have that in-system ability, they'll jump in, get hit by a salvo of SMAC rounds before doing an in-system jump and plop themselves right next to the SMAC guns and destroy them in a single volley. So really, SMAC's wont be THAT effective.
Actually, this brings up a question about the in-gravity well jumps, who came up with that? I mean honestly, you can't get a more OP'd ability. It makes any sort of defense utterly pointless since you can just jump yourself from one side of the gravity well, to the other, and then jump yourself right out there. How was this even supposed to be balanced?