Okay so this is a bit of wild idea I've had my head for a while now basically I good twist would be for a female Chiss to show up with the intention of bringing him back but to meet and fall for Ezra. I think this would be interesting for a few reasons because so far we've seen he's duplicitous.

However he does what he does for his people so I'd be very interested in seeing what Thrawn would do if presented with a peaceful option of returning with Ezra and agreeing to not start a war. Essentially getting an offer like "Look the Empire is dead and the Republic is incompetent but our people are in talks with them and while they are idiots starting something with them will not do our people any favors.

Another reason I like this idea is it would show how far gone he might be to refuse an option like that. Especially how in the Heir To The Empire Trilogy he refused to acknowledge the war was over.