Before the dark times…before the prequels…I remember that Palpatine and the Empire were supposed to be so racist that they seldom utilized elevated alien species to high ranks. This accounted for the lack of aliens in any Imperial vessel in the OT and made characters like Grand Admiral Thrawn seem even cooler and more impressive. When the PT negated that with the characters shown here, I was tremendously disappointed. It took away from the evil of the Empire.
The way I see it, the Empire is racist but the Emperor is not. To him racism is just a means to an end. When it’s helpful by allowing slave labor (I don’t see why they wouldn’t just use droids, but whatever), he’ll enforce racist policies. When an alien like Thrawn proves himself a brilliant strategist, he lets him in anyway. The Empire as a whole is still very much racist.