Not real advice, but I'm in a somewhat similar situation. While I really like the game, every single game has been a struggle and the outcome a loss.
My feeling is that KoW really is a delicate game, and you need to think ahead maybe even more than with Warhammer Fantasy prior to the 8th ed. Even if you can measure everything. Likely this is due to less practice. Even math-KoW might help to understand the nature of various unit confrontations better.
There are strong deathstars in the game for most armies, but they tend to be hordes, and could be maneuvered and flanked. Frontally engaging those units with anything weaker, not to say regiments, doesn't work without flanking. Still, I haven't been able to achieve a single flanking against them. It's hard to say if this is because of little practice or because of the basic nature of the game. Possibly you should go for two hordes in a list for a starter.
Empire style/skill artillery and shooters are clearly weaker in KoW. I still feel they have a role, but what exactly, I haven't been able to deduce.
I've never taken a monster/tank in a list, nor ogres, nor knight regiments or hordes. They could bring some needed muscle and maneuverability with narrower frontage. Hard to say. Must practice more.
-Z