I think I already know the answer, but...

If you had a novel with requested revisions on it, but they were nebulous ones, like strengthening the emotional connection to the MC, making her drive the story more, making her not so clueless in other parts, and fleshing out the worldbuilding, and

you had a half-written novel about something completely unrelated (no doubt with some of the same issues going on), also with interest from the same source,

which would you do first? And why?