Every class that has a set rotation (as opposed to the priority system that summoner, bard and machinist follow) which has one of three purposes:
-DoT rotation; sometimes tied to your main damage or buff/debuff rotation; shadow fang, chaos thrust, goring blade etc. they're your strongest attacks if allowed full uptime. Not every class has a full rotation per sé, but as a stand alone attack that should be used as soon as it expires like; mutilate, scourge, fracture etc.
-main damage rotation; aeolian edge, full thrust, snap punch, butchers block, royal authority, soul eater etc. these do the most immediate damage and (apart from butchers) have no other side effect as opposed to DoTs being the most damaging with the catch being, they have to be up for the full duration.
-buff/debuff rotation; armour crush, dancing edge, dragon kick, disembowel, delirium, storms eye/path etc, these enhance other abilities and are to be upheld 100% but the trade off is that they are almost always your weakest rotation (dancing edge should be used instead of aeolian edge in situations where you cannot meet the positional requirement)
if SE was to follow this like they have with pretty much all classes so far then no, Samurai's slashing debuff ( if it even gets one, for all we know they could have a slashing buff for themselves instead of a slashing debuff on the enemy making the class more selfish like monk) will never be stronger than the main damage rotation. I hate to say this as a warrior main, but the problem is warrior. Warrior not only has highest personal dps but it also brings utility. It has evrything.
thats like having a monk with the highest personal dps + the ability to use shade walker, smoke screen, battle litany and trick attack. Warrior has it all. You wither take away storms eye from warrior and all tanks are equal. ninjas will be a bit upset but at least warrior isn't mandatory oooor you can give paladin at the very least it own version of storms eye and now paladin/dark knight compositions are more viable.
Edit- Now that i think about it, if SE realy cared about tank balancing, they'd change the way storms eye works by making it give warrior a personal slashing buff (or get rid of it all together and buff maim(which cannot stack with dancing edge and whatever slashing debuff samurai gets)) and giving samurai the slashing debuff of storms eye . Samurai and ninja will now have synergy with each other and the tanks.