Warrior is by far the best subjob for monk in terms of damage. You can skill chain a little faster with /sam, but monk isn't about weapon skills, it's about damage over time which /sam does absolutely nothing for. Anyone who's sacrificing their DoT for improved weapon skill damage on monk is an idiot, guaranteed. That's not to say boosting your weapon skill damage is a bad thing, it's not; but the damage you do building up to that weapon skill will be much larger than the actual weapon skill damage and that's what is more important.
If you can't skill chain at least once per mob, you suck; if you do 2 or more during a single mob, your party sucks.