system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars (Rebels)] How would the Galactic Civil War been had Thrawn’s TIE Defender project was successful and mass produced?
gpt
First, Thrawn would have to convince Palpatine to invest in TIE Defenders instead of Super Star Destroyers (the Death Star was too far along to be halted). That's actually the easier part.

Second, the Imperial Navy would have to completely revamp its piloting program to accommodate for how advanced and expensive Defenders were. Even if they went into full mass production they'd have a shortage of qualified pilots.

What's most likely is a compromise that puts two or three Defender squadrons on a Star Destroyer as specialists while they keep the rest of the conventional fighters for mass swarm attacks. The Defender would essentially replace the Interceptor but be much more powerful. 

With this plan in place and Thrawn around to develop strategies, plus a new emphasis on pilot training and retraining, the Imperial Navy would become dangerously competent.