I never grinned for any Exotic Weapon or armor as there was no sure way of getting one. Not counting the exotics that are tied to bounties. In my opinion wanting to have all exotic weapons/armor be able to move up with you means there is no reason to try other exotic weapons/armor. Don't get me wrong weapons like the Necro and vex are a grind, really the only two that are. and with the Necro being as bad as people say, it should upgrade.