Sometimes the enemy drop weapons in good nick, but usually they need repair. Also, the guns wear out the more you shoot. Eventually, you will get a gun jam if you don't repair.
I know that and the idea of repairing weapons and armors is ok. I only believe that having to employ gunsmiths etc. to do these jobs, watch if they have enough to do and eventually sack them etc. could kind of overload the strategic part of the game. I would prefer the current design with some modifications. Major cities could be the places where you can buy and repair weapons and armors, sell stuff, heal your soldiers, hire squad members etc. So the players would be able to concentrate on the core of the game, which is assembling and equipping a squad with the gathered funds.
One final thought: You could maintain the current campaign mode as a "simple campaign mode" and add the strategic part you are currently designing as another alternative, "complex campaign mode". I see pros and cons for both modes and you would give players the choice whether to play a more or less predetermined campaign with a focus on the tactic battles or a campaign that allows them more strategic movement and opens a multitude of strategic options. IMHO the current strategic mode is almost ready to use, only some minor bugs can be found. So I don't see the need of stopping its development.
Ok, that's it for now. I will wait for the next beta to do some testing :-) Keep up this incredible work!