I think the Gith patrol was the primary reason they added the Flee button. If you trigger the fight with them, and you are only maybe level 2 or 3, run like heck.

One of the only playthroughs I survived against them was because I had Astarion run to Waukeen's Rest while they chased him. Everyone else was dead. With the Flaming Fist helping, I killed them, had Astarion run back and Revivify everyone. That was pre-Flee button.

I do agree. I think they've done pretty well. However, they REALLY fell short at the end of the Kith'rak Voss dialogue. It is totally out of character and makes no sense for him to pull a 1960s Batman villain moment where he says, "I'll report to the others. You, underlings. Finish them and bring the weapon."

No. He'd want full credit for it. He'd be like, "Quedenos. End them.". Then he and his dragon would butcher you, take the weapon and leave. That part is not done well. He needs a MUCH better reason to leave.