Modern Combat??? Like entire houses blowing up to grenade launchers? Like snipers going through three walls? Thermal vision, and like...INDESTRUCTABLE M1A1 Abrams!?!
Not with CoH mechanics. You'd need something different... like World In Conflict or EndWar (I loved EndWar... till the community died)
No, modern combat like:
1. Squads as in Coh2, with upgrades like grenade launchers, RPGs, heavy machine guns, better assault rifles, etc.
2. APCs, Tanks, built in the same ways. Rockets can miss, gun shots also, and there are so many counter measures on modern armor against incoming rockets, targeting systems and projectiles.
3. Rocket artilery, common artilery, Tomahawks and Scud rockets as call ins, etc. In coh1 you had v2, sturmtiger in coh2....
4. Buildable helicopters, working as any vehicle, being moved here and there, and just floating above the ground while iddle. Appaches, Hinds, Werewolfs, etc.
5. Off map air strikes, off map naval artilery, etc....
There are so many great features that can be implemented, realy. But we can just dream for now.