Yeah I agree with you on the triple wide being a detriment as far skirmishes are concerned. But the single player might be fun to have triple wide resolutions. I played DOW2 sp in triple wide and it was ok, it probably would have been better with just 1 monitor though.
DoW2 SP is an action-RPG, and there was little point in having massive FoV when half your map was FoW (so many acronyms). Playing it in 3x1 portrait was fun because you had inch size models and huge explosions.
One game I am eager to revisit is world in conflict.
But ya, RTS games have generally been pretty bad in surround. Most of the time the camera zoom limits any tactical advantage you might have, or the HUD is badly misplaced. Its funny cause google maps rocks.