This is the classic "Will my Duel Wielding Duskdagger Jotun Jarl get killed before he kills the fully equipped Bane Lord"

The answer is the Jotun will win 90% of the time.

Why? Just because of the law of Armor Negating weapons and modestly higher strenght weilders. Duskdaggers work fine on Banelords for the same purpose since they will never fatigue out.

Lifedrain weapons are not a must, they are a generality that is good for most situations because of their benefits, but by and large you will need a swath of different weapon combinations to deal with a competant enemy, not the least of which is a different confirguration of weapons.