Not just better but also richer

In among radio stories and marking OU assessments, a wodge of editorial reports, and assorted domestic stuff, I still have to find time to revise the current novel. This is not a mere editorial hop-and-a-skip through, sorting out typos, but heavy engineering. The novel's a single story, quite heavily plotted and almost thriller-ish, told by alternating first-person narrators, and I've decided to change the narrator for one of them. So I don't want to change the plot if I can possibly help...