Newer is not always better. ChatML is great in many ways, but for some use cases (like fiction) the old “instruct” non-chat completion models are better. However, they’re harder to keep “safe.”
I’m hoping trusted users might have access to a GPT-4-instruct or even a GPT-4-fiction in the future, but we shall see. (Maybe @AndrewMayne can be our Champion in our time of need? Small smile…)
Seriously, though, it all depends on your use case. It has become more difficult to get GPT-4 to stray from being a chatbot in some ways, but it is what it is, I guess. 