Oh the range/heal probably has less to do with DH and more to do with the fact that not only have they not added ranged specs, they actually removed one over the last 18 years. And since they probably want every new class to be hybrid (so they have something to fall back to if their dps sucks and can still do content) they felt adding a healer is a better choice (since healers just get more chances at representation than tanks do, both in raids and pvp)