I think that what should be done is increase the rewards (xp and gold) of every other game-mode to balance the equation. Some players who never played DTV on a regular basis play DTV now just because of the reward.
If Battle, Siege and Rageball had double reward, DTV would be the "least rewarding" again (and people wouldn't play it just for the reward), but, at the same time, the grind would be smaller, which I think would be good for attracting and keeping new players.