Ok, so we can’t really get too far out there before technology advances far enough to render it a moot point. So, what’s the absolute simplest situation we can consider? Well, I’d say it’d have to be a moon colony vs. Earth situation. Anything with only Earth parties involved doesn’t work - it’s too easy for land-based weapons to scrap satellites, and way, way easier for them to dodge. It’d be nice to control space, but I suspect that between relative equals, nobody would have any satellites left after the first day. The only exception I can see is having the foresight to seed sleeper missiles in orbit, and hope they can get through whatever anti-missile defenses exist, but I can’t see much benefit to that over cruise missiles.
So, in a Moon vs Earth case, what are the objectives? Well, I can see two possibilities - either you’re going to want to be able to threaten to smack the other guy so hard they leave you alone, or you want to be able to land troops. In the first case, all you need to do is have the ability to launch missiles that can avoid whatever defenses the other guy has long enough to hit the target - either by making them hard to see (bearing in mind that you can use ballistic missiles, maybe with rockets for last-minute adjustments) or by making them big enough to not matter - that’s Heinlein’s boulder-cannon. In either case, the critical thing is keeping your launch system alive, which shouldn’t be too hard, just stick it on a truck and keep it moving, and make sure you have a missile shield. This is basically just an extension of current missile-anti-missile technology, nothing really new.
The big difference comes with the strap-a-rocket-to-an-asteroid strategy, but that’s a tough one too. First of all, it’s expensive - even if you start with a space rock, getting enough fuel to move something that big into orbit costs a LOT. Second, it’s slooooooooow, and if you have the tech to move it, your enemy probably has the tech to move it back (otherwise, it’s not space combat, it’s a space massacre), so you have to put on extra fuel to account for that. I suppose if you’re willing to plan months-years in advance, you could pick a really, really far away rock and get it going damn fast, so your enemy doesn’t have time to move it, but now you’re talking REALLY expensive, and they might wonder about the conveniently-targeted, accelerating asteroid.
Ultimately, I can’t really see manned spacecraft ever getting in a fight. Your ultimate targets are going to be stationary, and it’d be as easy or easier to launch missiles from the ground to intercept as from a spaceship. Depending on how good missile shields are, it’s either going to be a nuclear standoff, where everyone has the ability to kill everyone else, or a game of deception - no, really guys, that’s a freighter, and OHLOOKWEDECLAREWARTHEREGOESPARIS. As soon as two entities are at war, any non-missile spacecraft get royally smacked, and the political process determines who’s still alive.
As a final caveat, the Battlestar scenario, where you have space combat by dint of not having a planet - I still suspect missiles and flak rule the day here. The size of vessels that would be needed for large populations are essentially locked down by inertia, and function pretty much the same as planets for these purposes. One side fires missiles, the other side tries to swat them, rinse and repeat until somebody goes splat. There’s no benefit to having manned fighters that isn’t vastly outweighed by cost.