I hadn't had an exotic or leg weapon till somewhere around lvl 25 I now own 2 exotic primary 1 leg primary 4 leg secondary 1 leg heavy. I also have 1 more exotic I am working on and one a abandoned recently since I had 3 slotted in my inventory which made normal bounties annoying. I am level 28. If you focus on levelling the cryptark you ll have chances at leg also for each level pass lvl 3 for that faction example vanguard new monarchy you will receive a leg item from their shop for free. I don't see the point of farming for legs. They drop randomly and you just have to be patient. Focus on doing raids and levelling up factions