Since this thread has popped back up, I just want to say I'd like a strategy game that focuses on the long game.
So it would be one where you actually fight out the battles, but you don't have to win every battle to win the war, and it is in fact sometimes necessary to surrender certain valuable assets or troops so that you can take them back and use them later. Or you might want to retreat from a battle, and it's not some objective saying you need to do this, it's a call you make on your own judgment of the situation.
And there'd be no obtaining resources so that you can obtain more units in the middle of a battle. The only way more units will show up during a battle is if reinforcements arrive, which is something you'd need to set up ahead of time, or maybe you could send a messenger to call in reinforcements if they happen to be somewhat nearby.
Capturing resources would still be useful, though, as you'd need to feed your troops and sometimes replenish and repair their equipment. And though it wouldn't be feasible to build anything but simple structures on the battle timescale, between battles you can build things like wooden fortifications and siege engines, and maybe things like stone fortifications and ships if there is enough time between battles (you'd be able to save progress between battles, of course, but you'd want to be in a safe place to do it so that the enemy doesn't just kill your workers).
And you shouldn't be able to just spawn troops out of nowhere. If you were in your home country/city-state, you could recruit troops from your populace, but otherwise you'd need to convince natives of the area you are in to join your cause or work as mercenaries, you'll have to wait for reinforcements to arrive at your location.