sins have more luck - 50 weps for example, cant get the 50 warrior wep past luck1 due to the DC gap, also every 7th bene or so curses it back to luck0. agil more than makes up for extra HP, you of all people know this.
warriors CANNOT solo the same bosses as sins. trust me, i've tried just to prove this point. and even if some of the same bosses are soloable, it takes much, much more investment in kit and more effort on a warrior than on a sin - OK is an excellent example of this.
OmaKing hits on a % attack, so it's hardly fair example to use. A level 33 Sin can kill one easier than I can at level 51 also.
It's just as hard to luck Sins 50 weap too. We've seen a luck 6 DSS ingame too, so not always true. (DSS DC gap is 35DC... 26DC gap difference on 43 Sin weap, and we've not seen one past luck5).
Yes agil is great, warriors can also stack some of this on their kit. I would rather have 200+ HP more. DC is sacrificed for Agility. Warriors will always gain more DC with their % based Rage also. They also have a lot more AC, and a skill which also lifts this. I'll test with you to show you that AC DOES make a difference in hits.
ShadowStep is great yes, it's good to be able to get in next to people, but with the low HP pool, the can still be 2 hit by warriors, archers and wizards. It's also an escape skill, to get out of the way, which has a chance to fail, and when it fails with our low HP, its death. Warriors dash won't ever fail, and also take no damage when using.
Both have their advantages across the classes, sins should be a higher speed, less high damage, more average. Warriors slower speed, higher tanking capabilities, and chance of higher top end.