You can craft medium armors with tier3 materials that makes them open to all classes, then put cunning on them. Or you can just craft heavy armor with strength.
I've been using Iron Bull as a pseudo-dps SnS warrior. At level 22 he has:
1. payback strike+
2. lunge and slash+
3. shield bash+
4. war cry
5. bull rush+
6. horn of valor+
7. combat roll
8. challenge+ (you can use mark of the rift/rampage here, I play without focus abilities)
Cutting Words (Vanguard, +20% dmg vs. taunted targets)
All the reaver passives (no dragon rage)
Flow of Battle (2h tree, reduces cooldowns by 1 sec on crit).
He doesn't really compare to a rogue or proper 2h reaver in terms of damage, but he adds alot of support damage (35% from horn and 20% vs. taunted for the whole party), great detonations and insane guard damage. He regularly crits for 20k+ with shield bash on guard. Pay attention to your weapon's damage (not DPS) stat, longswords in particular usually have really high base damage, which is what your abilities take into account for damage calculations.
Oh and use +% damage per nearby enemy along with hidden blades masterworks. That's how you get those insane damage numbers. You can also go Champion and get To the Death+ for the insane damage buff (but you lose Reaver passives).
TL;DR SnS can work as buff monster + decent damage, the key is going heavy on none-spec trees.