I disagree with the part about using strats to effect hanger downtimes. Strat objects should only influence a country's effectiveness to conduct battle (fuel, ordnance, radar, etc.), not prevent fights entirely. To be honest, I only attack resupply vehicles (barges, trains, convoys) as "targets of opportunity" for personal points rather than aggressively seeking out their destruction to prevent the enemy from regaining supplies. I'd certainly be in favor of increasing their importance as an additional element to the game.
As far as strat factories go, I'd like to see the strat system set up on three levels: central city/strat, regional town/strats and friendly fields. Instead of directly supplying airfields, vehicle bases and ports, city strats would supply damaged regional factories. There would be two sets of regional factories, each set supplying friendly fields along the respective front (half of the country). These strats would be located separately around the country and would supply damaged fields as allowed by the repair model. Each of these local strats could be tied to its own town including a map room, allowing the factory to be captured (just like a field) by encroaching enemy forces. Captured factories could then further decrease the repair time for local fields under the controlling faction. Meanwhile, fields that were originally supplied by the captured factory will experience downtimes of destroyed field objects increased to the maximum limit (unless supplied by players from nearby fields). Damage to the central city/strat would effect repair times for all friendly strat factories of the particular type. Damage to a regional town/strat would only effect repair times for particular field objects on fields within its sector. I'd like to see player controllable defenses at these strat sites as well.