In the games of KOW we have played I have seen Tactics used that would never work in WHFB.
Me and my opponents have used feints, kept units in reserve (and I mean behind the main defensive line not off board), Columns of units in the attack, cheap screening units to disrupt the enemy advance. Stuff you would dare not use in WHFB as the game mechanics were too complicated and clunky!
In all games we have played generally the better tactics have paid off, although outrageous dice rolls have changed the fortunes in some games (but thats true for any game involving dice).
I have not lost or won a game of KOW due to 'technicalities' (i.e. I thought I could make a manouver or an attack and it turned out I couldn't) sadly the same is not true of WHFB.