DC-Custom Cherry : Nice looking guitar with a dull sound

First, the good part - I love the looks, and it's made fairly well. No fret sprouts, the binding is decent, and the action is low. The only quality issue was that the bridge was not properly grounded (the wire was just hanging in the cavity unattached), so I had to fix it myself, which wasn't too hard.

Features-wise, I'd like to have coil split push-pull. I think the recent versions already have it, though mine didn't.

Now the complaints. It's the sound. Compared to all my other guitars, this one sounded dull, dark, flat, and uninspiring. Because I liked it otherwise, I tried changing the pups: tried various humbuckers and even a set of Phat Cats (which sounded fantastic on my Epiphone Les Paul) - nothing helped. I managed to get out of it more or less decent high-gain metal tones, but it could not do anything else properly.