All the examples of "warmer" generations show that OpenAI's definition of warmer is synonymous with sycophantic , which is a surprise given all the criticism against that particular aspect of ChatGPT. I suspect this approach is a direct response to the backlash against removing 4o.
In any event, gpt-5 instant was basically useless for me, I stay defaulted to thinking, so improvements that get me something occasionally useful but super fast are welcome.