I have every exotic except Necrochasm. But I really do not believe in all the pure RNG thing. Of course Bungie has a system to keep as many people as possible playing for a long time to get a desired weapon. I don't think there are that many people who have all exotics, otherwise the playerbase would fall off very fast if everybody got what they wanted. I also made an interesting (subjective of course) observation concerning exotic drops: Everytime I concluded an exotic bounty (I'm happy to receive the SGA bounty all the time, easy to finish) more exotics seemed to drop from CE, VOG etc. The week I concluded 2 bounties on two of my three chars, I received Hawkmoon and Red Death, the only two exotic weapons-except Negrospasm- that didn't drop for me so far at that point. Just a personal observation though, but keep on doin' the exotic bounties and see if it leads to more exotic drops...