Cons
You have to be in melee range.
Takes up 2 slots.
Only contributes once towards armor sets.
Glyphs are doubled in power. (Can only use 1 type for 2 slots).
Traits are not doubled in power.
Slow swings.
Hit only about 25% harder than 1 handed weapons.
Uppercut skill is too slow.
Momentum only useful on long fights.

Pros
Look badass!
Critical Charge - utility and damage.
Reverse Slash is nice.

Suggestion.
Currently Battle Rush skill has 2 ranks at level 41 and level 50. Each rank gives 15% increase to stamina gain after killing an enemy for 10 seconds.

- Change it to three ranks; Levels 21,41,50.
- Each rank gives 10% stamina regen after kill.
- Ranks also give 3/6/10% mana regen after kill. For greater synergy with class skills.
- Ranks gives 11/22/33 chance per weapon swing (normal hits only,not skills) to stun the target for 1.5 seconds.

Considering destruction staff knockback capabilities and the fact that one is used at range while the other is slower and you have to be much closer I don't think that last addition is at all unreasonable.

"After kill" should mean if something dies and you get xp. Not something dies and you were the last to hit it.