Write Away

I'm glad the review doesn't come across as off-base to someone who read the book. Like you (assuming I understood your meaning correctly), I think this should ideally have been two books. Rather than telling writers they're all imperfect and should be perfected, which seems to me a weird reflection of the salvationist character arc, I believe the better approach is to accept that different types of writers are going to write different stories and that's okay. Sure some character-centric writers are going to write meandering and boring stories and some plot-centric writers can't do characters worth a damn, but in my mind the solution isn't to converge them into one being but rather to work on their divergent strengths. Character-centric writers are going to plot differently than plot-centric writers do, and plot-centric writers are going to characterize differently.

Rather than trying to teach both types with the same curriculum, therefore, I would go with a co-teaching approach like you mentioned. I'd tell character-centric writers to brainstorm actions their characters would take, then see how characters build off each others' choices, escalating things until they reached a breaking point. I'd have plot-centric writers work out their plot first and then reverse-engineer from there, questioning themselves about the characters who would act this way. They'd flesh out characters accordingly and even modify the plot if it turns out plot requirements make the characters inconsistent or incoherent. Leading with strength is usually a better idea IMO than trying to fit everyone into a single ideal.