@
anaxie
Sylvanas's crimes:
1) Human Testing for Biochemical Weapons. She was in control of the Apothecaries when they captured humans and dwarves to test their original plague on. And even -after- the events at the Deathgate, she still had her people capturing humans and dwarves and feeding them plague-tainted food to test the efficacy of her "Living-Only" plague.
2) Torture. She does it. Yeah, so do many other people, but that doesn't make it okay.
3) Use of biochemical weapons in civilian-inhabited areas. The big issue of Mustard Gas that lead to it and other forms of chemical and biological weapons being banned wasn't what it did to the soldiers, but what it could do to civilians downwind, or who were later exposed to residue clinging to objects. Sylvanas has ordered the plague used in places like Southshore where civilians are in the area, and it's not like she couldn't know that it was going to wipe them out, too, in a gruesome fashion.
If she were to use the Plague in Tirisfal Glades, or in places where there are no Civilians (Like Gilneas City once the civvies were evacuated because of the Worgen Curse) that's cool 'cause it's being used against soldiers and civilian casualties are minimal.
That's really about it, to be honest? But one of those is a War-Crime and the other is a Crime Against Humanity (Or... Personanity? Whatever word would apply that makes it more all-encompassing than just humans because Warcraft races).