We frequently hear the word "honor" in Warcraft - heck,almost on every turn. Saurfang is all about the honor,Anduin can't say a single sentence without mentioning the honor. All of the orcs have saying "strength and honor". Baine is all about the honor. What the honor actually is?
Is the honor about the waging war in a fair melee combat? Does that mean,that an orc warrior,who has a strength of three Stormwind humans,should charge into battle only when there're 3 or more opponents otherwise it would be honorless to fight against those,who are weaker? Does that mean,that all spellcasters and hunters are honorless cowards,because they don't engage in a melee combat? Are the rogues honorless scum,because they attack somebody,when they least expect it? Is the honor about sending thousands of troops to certain death only because the fight would be fair,instead of using siege vehicles or catapults?Is the honor about attacking unexpecting kingdoms and burning them to the ground when they least expect it?
War is war. It's ugly, it's horrible, it's a nightmare,but damn,war is not about the honor. Sylvanas at least never said,that she cares about the honor,all she cared about were her goals. Saurfang,on the other hand,a veteran of all wars,who taught Garrosh about honor,was all for the war against the night elves up until the moment he threw an axe in Malfurions back. Like when he attacked the night elf lands and slaughtered a bunch of them was about the honor. The only thing he regretted was that he didn't charge Malfurion when he saw him. Heck,Saurfang was up for the whole faction war,even if it would lead to another destruction of Stormwind to ensure Horde's future.
World of Warcraft is all about the war and that's it. Honor is just a nice thing to mention from time to time to paint yourself whiter than your enemy.