LOL, which class is not like that? Most WDs play the SB set, most Barbarians play the Wastes set, most Monks play PoJ, most crusaders play AoV, most wizards play Vyrs, etc. Whichever set in a class is most powerful will be played by the most players.
Boost the new DH and Necro sets really high initially, let them shine for a season, and then worry about balancing them, and other sets, in the balance patch(es). One of the best parts about patches is that they do change the meta so that you can try different sets every season!