I think maybe once or twice a year, there should be a contest where the Destiny community gets to submit exotic weapon ideas(anything from a spread sheet with the main perks and concepts to a fully rendered object) within a certain period of time, then the community gets to vote on their favorite and the winning gun gets released into the game, with the winner of course being the first to get their gun.
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My exotic submission would be dual sidearms with explosive rounds, firefly and a perk similar to the red death where precision kills regenerate health. They would do solar damage and the skin of them would look as if they were recently taken out of a forge(black and gray, with a glowing orange/red undertone)