I personally would like to "fix" the thinking when it comes to asking these models for help on more complex and subjective problems. Things like design solutions. Since a lot of these types of solutions are belief based rather than fact based, it's important to be able to fine-tune those beliefs in the "middle" of the reasoning step and re-run or generate new output.

Most people do this now through engineering longwinded and instruction-heavy prompts, but again that type of thing supposes that you know the output you want before you ask for it. It's not very freeform.