Sabine using Ezra's lightsaber is <3 "We have to prepare for the worst" Because at the end of the day, an Empire led by Thrawn is far more efficient than an Empire led by Palpatine
The main thing is that it's going to be tricky to characterize Thrawn in this upcoming series if you consider Thrawn in the canon novels. The worry is that he'll be a relatively generic villain who wants to revive the Empire cuz evil, but in the novels he was always loyal to the Chiss Ascendancy and his loyalty to the Empire is to further the Chiss cause
Fun fact, the Chiss has Force users of pre- and teenage girls who lose their Force sensitivity once they get closer to adulthood (Wait, that's basically Strike Witches' conceit wtf) who the Chiss use to navigate through Hyperspace because the Unknown Regions is largely unmapped, and they're called Sky Walkers
the fanfics of Ezra and Thrawn largely circulate around Ezra finding out about the Skywalkers and helping figure out why they lose their Force sensitivity
"We have to prepare for the worst"
Because at the end of the day, an Empire led by Thrawn is far more efficient than an Empire led by Palpatine