You've practically brought all of the exotics up to year 3 at this point. The only ones really missing are the trophies of all exotics in year 1. The [i]truly[/i] exotic guns of destiny. Vex Mythoclast and Necrochasm. I don't see a reason for it not be brought to year 3..
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To get y3 vex there should be a quest where you hunt down xylar