Thrawn being an alien was meant to establish his credentials as a badass.As for the EU, I read a couple of the Rogue Squadron books (I should read or at least listen to that whole series again) and liked those ones.
But even the Thrawn series was a yawn (a blue guy? Really? When the entire Imperial force was shown to be human(like) in the OT?) - the 'humanicentric' thing was a subtle point about their doctrine in the OT. I don't remember the stories well enough to remember if they explained it away, but coming from the movies, I couldn't buy it for a minute.
As for the rest (except for the X-Wing and TIE video games - they were a quasi-religion for me for quite some time), I'm ignorant of it and don't feel the least bit sorry...
Not in the Empire. If he wasn't a bad-ass Sith, he never would have achieved a prominent position in the Imperial hierarchy or even gotten into the Academy (just going by the subtle, unspoken, quasi-nazi Imperial doctrine as shown in the OT). The entire premise of the book broke SW-Universe 'canon' (as shown in the films), at least for me.
And yes, I fully realize this is a fictional universe, but consistency matters.