While it would be good to have more variety of aircraft in DCS I don’t think the typical civilian aircraft would be an ideal fit for DCS’s uniqueness of tactical and mission planning anytime soon.
However DCS would be ideal for another civilian sector, Firefighting! Instead of dropping munitions you could drop water and fire retardent’s on wildfires. That is something that would actually go along with DCS’s style of mission planning and accomplishing missions. I could already see using a firefighting version of the Heuy DCS already has to go drop water on a site and after the drop you fly to the nearest lake to refill and back again until the fire is out. Then it would be cool to use other fixed wing aircraft such as the C-130.
I would imagine that DCS could potentially attract far more VR pilots if it featured firefighting aircraft and associated missions than just regular civilian flight of which there are already plenty of other competing sims for that. But next to none that I know of that feature fire fighting aviation.