I know this suggestion isn't new, but it's new for me, so I'm hoping by bringing it up again it may gain some traction.
Explorer badge, visit and hack unique portals, has a layer. (Though I wonder if it ought to more correctly be "visit OR hack".)
Pioneer badge, capture unique portals, has a layer.
Unique portals drone-visited has a metric tracking it, but no layer and no badge.
Scout controller has a badge, but no layer.
I'm suggesting a new way of presenting all the uniqueness layers where each layer's colour is isolated to a quadrant of the uniqueness presentation, so the wheel would be progressively illuminated as you acquire the different kinds of uniqueness for that portal.