It seems like GPT-4 is going to be coming out soon and, so I've heard, it will be awesome. Now, we don't know anything about its architecture or its size or how it was trained. If it were only trained on text (about 3.2 T tokens) in an optimal manner, then it would be about 2.5X the size of Chinchilla i.e. the size of GPT-3. So to be larger than GPT-3, it would need to be multi-modal, which could present some interesting capabilities.
So it is time to ask that question again: what's the least impressive thing that GPT-4 won't be able to do? State your assumptions to be clear i.e. a text and image generating GPT-4 in the style of X with size Y can't do Z.
Write semi-convincingly from the perspective of a non-mainstream political ideology, religion, philosophy, or aesthetic theory. The token weights are too skewed towards the training data.
This is something I've noticed GPT-3 isn't able to do, after someone pointed out to me that GPT-3 wasn't able to convincingly complete their own sentence prompts because it didn't have that person's philosophy as a background assumption.
I don't know how to put that in terms of numbers, since I couldn't really state the observation in concrete terms either.
Have you tried doing this with longer prompts, excerpted from some philosopher's work or something? I've found it can do surprisingly well at matching tone on longer coherent prompts.