instead of going left to right, even with a scratchpad, maybe you start with a rough shape of the big picture all at once, and then you iteratively resolve and things come into focus.
mercury (https://www.youtube.com/watch?v=2fDBeMu6xjk) seems to have made the most progress here, which is not saying a ton but is not nothing. i do think it is telling that of the big labs, only GDM has made any meaningful bet on text diffusion. you can bet your ass all of them have evaluated it for a source of alpha.