It may be dependent on your build, Rogue was the character I beat the campaign with first and got to WT4 first, it was pretty painless.

Used melee Flurry/imbues with Close-quarters combat and combo points. I think it helps that most of the core skill aspects for Rogue (flurry, TB, Barrage) are available from the codex, so you don’t need to rely too much on drops.