Some of the best ways to make the WAAC players get knocked down a peg or 2 is make up special missions of your own. Create stories and scenarios that have weird objectives that the min-maxers might not be suited towards, but your average army will be.
Or, in my experience, force them to play the new Maelstrom of War missions. WAAC players hate those missions with a passion, as the games are much more random - And random is fun... Unless you are powerplaying.