Albert Pujols' has virtually no correlation between BA and IsoD (-0.37 correlation between high BA and high IsoD), which is contrary to your position. Lance Berkman does a better job of slump-proofing than Dunn (-0.60) and that's also not good for you. The one thing that's coming out of this isn't just that high IsoD hitters are more slump-proof than low IsoD hitters, but that some of the former actually appear to make up for lacking hits by pushing their IsoD numbers even higher to compensate while slumping. You might think that your position is intuitive, but it's also inaccurate.
And if you're getting pitched around, you still have to choose not to swing at those pitches. Trying to discount those isn't something you'll be able to do because worse hitters swing at those pitches.