Honestly, Gale has been trolling this entire time. What happened to her conceptual talents, especially that Ego ability? She really could kill the whole team any time she wants but just does not. I hope she's still alive otherwise it just feels like author makes her too strong and no longer know how to properly get rid of her.
Yeah, she was playing with them. Especially during the first Ego, she didn't consider them a threat at all anymore.
She was completely winning up until the point where Touya revealed Alexander's arm. And after that, Gale was way too upset to see that her idol gave her arm to a nobody like Touya that she didn't even notice Ein's beacons. At that point, I can see why she would not use her conceptual talents, especially since they are based on a perfectly calm mind. There were also a few things that may have impacted her decision : the fear that a Firstborn's arm could tear through conceptual talents as well, and Picasso's paintings, which Picasso said would work "anytime, every single time". At that point in the fight, she was both in the wrong mindset and would risk a lot by using these talents.
And after "Flower Petal", she lost control of her talents, so conceptual talents are out of the question. You don't want to get ripped apart by your own ability.
I don't think Gale is dead, but if she died here I would not be upset.