When they released GPT-4.5, it was miles ahead of others when it comes to its linguistic skills and insight. Yet, it was never at top of the arena - it felt that not everone was able to appreciate the edge.
No, GPT 5.x are very unlike GPT4.5. GPT 5.x are much more censored and second-guessing what you "really meant".
When it comes to conversation, Gemini 3 Pro right now is the closest.
When I asked it to make a nightmare Sauron would show me in Palantir, and ChatGPT5.2 Thinking tried to make it "playful" (directly against my instructions) and went with some shallow but safe option. Gemini 3 Pro prepared something much deeper and more profound.
I don't know nearly as much about talking with Opus 4.5 - while I use it for coding daily, I don't use it as a go-to chat. As a side note, Opus 3 has a similar vibe to GPT 4.5.