When shooting down satellites is done reliably and routinely, then I'll pay attention. Until then, it is simply a series of tests whose inclusion in the game would be debatable, just like SDI.
My point with the satellite comments was that everybody seems so hellbent on every feature in the game having some sort of counter. I'm sick of it. Let's face it--there are some things in life that just don't have a proper counterbalance. Nuclear weapons are the best example. Even with SAMs, enemy fighters, and a potential SDI system, there are too many ways nuclear weapons could make it through and not be intercepted. I don't want satellites to turn into another feeble ICBM-like feature, where you could just build something new to counteract them 75% of the time. It gets old fast.
Reliability and routine? The reason anti-satellite tests were stopped was because of treaty and cooperation, not for lack of capability (although the former would be interesting to mod). The U.S. has more than enough ability to do so: it just doesn't test it. And after all, this thread is talking about stuff that hasn't really been fully developed yet, or even at all (mechs).
The question is game balance. Nukes don't have a proper counterbalance yet in real life. I'm cool with that, although it does leave open the possibility of SDI (which I'm skeptical of in real life, but that doesn't necessarily bear on the game). But satellites - there are ALREADY counters to them. This can include things like shooting them down (which were being developed 20-30 years ago). And there are simply people hiding, which goes to the stealth question.
I think satellites are an interesting idea to implement, and I would personally favor some implementation that allows you to see 3x3 or 5x5 areas. But, there are other issues, like what happens to the recon function of fighters? Or can this functionality be modded more effectively by having unmanned drones in the game? If I were a programmer, I would prefer a unit rather than the complicated elements involved in making satellites work in game.
To bring this back to the thread's question, I would implement the following units:
1. Parachuting light tanks and artillery, with an additional movement point
2. Stealth units
3. Drone recon units, which are cheap, can move fast, reveal stealth, but are particularly vulnerable to anti-aircraft fire
4. Cruise missiles
Near-future or current equipment which can redefine how combat takes place in the late game. And everything, with the exception of cruise missiles perhaps, can be done based on the improvements that Firaxis is already implementing.