I never read the Thrawn books as a kid, but I feel like that character can't fully operate against anyone but the main trio of Luke, Han and Leia. In a way, Thrawn was kind of a "crit confirmation" to use some RPG jargon -- like, alright, you beat the evil space wizards and broke the Empire, but was that a fluke (Fluuke?) or can you do it again?
That being said, I hope Ezra takes more of a center stage in the fight against Thrawn going forwards. He was one of the better parts of Ahoska, and actually really love Thrawn as Captain Hook, with his own Peter Pan that he's unable to ever catch. Also, Thrawn has his own crocodile in the form of the space whales -- wait, is nuThrawn just Captain Hook?