I understand why they've done that - makes it simple to ensure compliance whether on the pickup, pickup with headache rack/ladder racks, fastback, open air, or SUV body kits - but given the increasing height of vehicles Slate will share the road with, I'd love to add a high-mount third (fourth) brake light to mine.
Some ditch lights/bed lights wouldn't be amiss either, and I've always liked the look of the tailgate light bars. Maybe a tailgate light bar routed across the ladder rack?
More light is better, as long as it doesn't impair the vision of drivers around me!