When the day comes that sharing XP by playing as a second support on the top lane creates more pressure and gives the same or better XP than jungling.
Junglers are already 2 levels behind solo laners. But if Riot goes through with their promise to further reduce jungle XP, I'm a bit concerned. I see visions of a meta that consists of nothing but chain ganking assassin junglers. Or worse, a meta of a second support going top lane.