In the latest issue of The New Brewer (Sept/Oct I think), Matt Cole of FatHeads Brewery mentions that significantly restricting the use of crystal malts when brewing an award-winning IPA is a must. He does have a track record of a number of IPA medals at WBC and GABF, so that advice should have some weight.
When you think about it, when brewing a hop-focused beer, keeping the malt presence down at an appropriately low level should help accentuate the hop bittering, flavor, and character. Adding a larger percentage of less fermentable sugars to your IPA wort does seem counterproductive.
Given that advice, I will have to agree that limiting the amount of crystal in a hoppy beer is a good idea. But that isn't to say that NONE is the correct answer. Adding just a touch to add flavor nuances that you CAN'T achieve with another base malt. For instance, adding a bit of a dark caramel note might call for a touch of a darker crystal.
Based on Matt's advice, I'd say that exploring the lower end of crystal percentage should be on the table for a number of beer styles.