You can find a list of all the Gallery Moderators here, so you can find the right person to send your suggestion to. My own DD suggestion guidelines can be found here, and if there's anything else I can help with, just shout
other reason; I do suggest DD's every now and then, the problem is that I'm pretty critical and I really need to be in total astonishment because of the deviation I want to suggest. It hasn't happened for me yet with any horror dev, I can remember. Or it did, but a few days later it gets featured, suggested by another person xD haha But I do suggest DD's in general.