Not sure who you are jungling with but most games that I jungle I am usually a level behind until about level 7 or 8 and then once i get 2 items and can start clearing camps fast I start outleveling my team hardcore. Riot can't buff the XP gain you get because if they did it would be like feral flare days where the jungler was level 18 and his team was 14.
Also, the gold income in the jungle now mixed with the global income means the jungler has more gold than ever before and that is evident in one of my recent games where our mid fizz went 9-3 with 197 cs and I went 4-2 as Udyr with 139 CS (most of it jungle CS) and I had more gold then him and I only had 2 more assists than he did.