I've skipped a few DQ's. Titan hunting is nigh impossible on a phone, and I just have no desire to try to farm and accumulate enough stuff to invent countless Mystic Pickaxes or try to break down half a grand items. Maybe if I had a real computer, I'd feel differently, but on a mobile device, such things are totally impractical at best, and way over tedious. Even walking several hundred tiles is a chore and a half when on a 3.5 inch screen.... It would be nice to have an option, whether or not one is so inclined to utilize it.
That said, I can see how this could be a problem in itself, as it could deter from the purpose of the DQ's which are to give us incentive to try the whole game, which in the case of a newer player or a die hard "leveler" or "pvper" (I have always hated these labels btw) could have introduced them to aspects they may not have tried otherwise. That in itself should be reason enough for a re-roll to be only for classification of the DQ rather than what type it is. Myself, I would be rerolling less for the reward involved than for more a more viable version of the task at hand...