The Warden > Hawke. There's no debate.
The Warden killed/defeated 2 Pride Abominations (Uldred, the Baroness), 1 Pride Demon, 3 extremely powerful blood mages one of them a Magister (Caldrius), Gaxkang the Unbound, 3 High Dragons (one of them was Flemeth), 1 Varterral, the Queen of the Blackmarsh, the Archdemon Urthemiel, the Mother, the Harvester, and thousands of darkspawn. (Not counting diverging enemies like Caradin or Witherfang)
Hawke's killed Corypheus (tops his list), Xebenkeck, Maybe the Arishok, Maybe Danarius, 2 Varterrals, 1 High Dragon, Red Lyrium Meredith, Harvester Orsino, 1 High Dragon, 1 Pride Abomination (Marethari), and hundreds of demons.
Hawke's tough, but is not on the Warden's tier of badassery yet.
When you consider that the Warden accomplished all of this within the span of 2 years as opposed to 7 it makes the winner a clear case.