They would be completely relevant. That would be three new sets of gear for people to collect, all of which are infusable and can reach the max light level. It would also bring some much loved weapons into year 2. If all the raids dropped end game gear then it would be way to easy to reach the max level, and would also depreciate the value of the King's Fall raid (because lets be honest, Crota's End is 100x easier than King's Fall).