...and they actually fit together pretty well, as Ghavrel pointed out. In addition, the Trolls and Orcs are very different groups of Trolls and Orcs than the ones that Silvermoon has a history with. And the Blood Elves are no strangers to the idea of abandoning aspects of their heritage, so they don't hold the Trolls and Orcs' races against them.

Warcraft 3's story had it's ups and downs, but the best thing to come of it is Illidan as a character. He's the most interesting person in the entire mythos. He's also integral to the Blood Elves, and they were loyal to him as of the end of Frozen Throne.

Which is why Burning Crusade, which flattened his character and turned him into a generic big bad so that faceless, nameless groups of massive shoulder-pad wearing players could kill him, was such a travesty.