Fair enough, we have different definitions of 'synergy' and, after further thought, mine is wrong. I withdraw my point.

I'm not precisely sure how Orks fare against DE, since I don't have the army any more and can't test anything. I would imagine that, excepting Lootas (which are still awesome), they wouldn't perform very well due to the weight of S8 shooting (dead Nobs, Wagons, Kans) and volume of fire (making numbers mean very little).