I guess I'll have to experiment a bit more with the Bomber/Stealth Bomber(which I actually haven't bothered to even build).
I haven't seen the Battleship or Artillery cause collateral damage while bombarding the cities defenses. Battleships can't do normal attacks against cities, and I already know the Artilery would most likely lose against Mech Infantry(assuming full strength).
I've only seen Collateral Damage go off in the event of a victory anyhow.
So looking at game mechanics, if Strength is capped at 40, the worst you could see is Mech Infantry and Modern Armor going against each other with 40 vs 40 stats, 50% chance of victory until attrition starts to factor into the thing. Which is why I said I have to wonder how they expect you to take a city in late gameplay with less than a stack of doom. Something they said they were trying to get away from.
Anyhow, I guess I'll have to see if taking to the skies helps with accelerating the attrition rate for the other guy(where it could still get nasty, between Bunkers, Fighters, Jet Fighters, SAM Infantry, and Mech Infantry all can play into countering your bombers). Too bad the guys in the world I'm playing on right now have nothing more advanced than Riflemen for defense.
EDIT: Will tack this on, *crosses fingers on the strength cap being a bug*
SAM Infantry 18 Base Strength, Infantry 20 Base Strength. Marine 24 Base Strength, Navy SEAL 24 Base Strength
Training received: City Garrisson I (+20% city defense), City Garrisson II(+25% city defense), City Garrisson III(+30% city defense),
Other Modifiers: Fortify(5 turns, +25% Defense), , Hills (+25% Defense).
Total Modifiers: +125% Strength
Modifiers considered:
SAM Infantry 40.5 Strength(0.5 over the evident cap)
Infantry 45 Strength(5 over the evident cap, can fortify in a city on any other terrain and hit 40, or simply sleep in a city that is on a hill tile, no need to fortify)
Marine/Navy Seal: 46 Strength(pretty much the same as Infanty, except if built to defend a hill square, City Garrison III isn't needed anymore in exchange for 5 turns+ of being fortified in a city)
My vote is rapidly moving towards bug on this.