No new classes, please.
At first I thought the comparison at the top with "Good, neutral, bad" was sort of silly, but it makes a point in an odd sort of way. (Where does a Shadow Priest fit?)
I expect either:
Dark Ranger or some such. With playable Etherals. Please. PLEASE? If it's a Tinker however, with guns and mechs, that won't immediately support the theory.
Also, I think Chaotic, Neutral and Lawful is a better analysis. And might be what Blizzard had in mind, moreso than Bad, Neutral, Good, at any rate.
Just give me cross-specs. In the vein of more options, cross-specs would be available to all classes or particular groupings of classes, and would change that class in different ways by granting it similar abilities that function differently depending on the class. That way, I could really get down and dirty with customization.
if the next expansion is the burning crusade 2: electric bogaloo, definitely so.