Oddly I think that Sun Tsu and other tacticians to indeed apply in a lot of ways to wargaming. Note that I say wargaming and not wargames.
Obviously you can't be wargaming with out a wargame but when you add in the human element and what you can do to your opponent through careful observation as to what their strategy is and what they hold dear you can apply the lessons of Sun Tsu in all sorts of situations.
It's amusing to me that you are literally applying the lessons of Sun Tsu to this situation. Where as I think that while they apply to warfare they apply to life more. Part of the basic framework of this game is an attempt to build a situation where the better tactician will win. That is a huge portion of the mitigation of the luck issue with the card mechanic. It is also why there is a certain level of terrain suggested.
I personally have not had an issue at all with a 2-1 situation. However with out actually looking at your play style, attitude and the situation they are placed in there is little I can do to help you get better.
You may well be setting yourself up for a more difficult row to hoe with an elite force over a horde but given many of the elite options that this game has there are a great many ways to off multiple models at once.
Now, if you are set on only a specific few models and those alone then you are clearly ignoring Sun Tsu completely. Case in point: would you bring cavalry to root out skirmishers in the woods? No. You would bring archers with fire arrows or siege engines to remove the advantage of those woods. So, look at your model choices. Look for things that can move quickly and hit multiple models at once. Bring models that have blast templates. Hide from avenues of fire. Don't present easy targets. Be sure to string your opponent out so that he has difficult choices and so that the swarm is spread thin. Use Terror to your advantage.
The list goes on.
@ Lucid: You are fired. Tacticians don't apply to tactical wargames? What?