I haven't bought many new DiMarzio's in the past several years, but of course I see them on many instruments, factory and aftermarket. In my opinion, the sound is fine, but they remain the least consistent of the major brands. I have found many times there is greater variance between same model pickups than with other manufacturers. And I can hear it too. It's okay though, because its minor, but don't be afraid to check yours if you get them. And don't be afraid to call them for a replacement if it doesn't meet your standards. I've never done it, but I'd like to call all the manufacturers and get them to tell me what THEIR acceptable tolerance fluctuation in the ohms reading, for example. You may get some interesting answers. Don't equate the wah or aw sound with an actual
wah pedal sound. Its just a way of describing the pronounced frequencies best they can.
I had to laugh because today I was reading an older Dimarzio catalog, and you'd think they were describing the sound and feel of a whole rig turned up to eleven. They talk about sounds that require certain preamps, cabinets, etc. saying that this pickup or that pickup does exactly that. So read their descriptions with a grain of salt, too, and accept recommendations from people here or on other good user sites before you accept their descriptions.