The Rochdale - Todmorden - Burnley route was actually the 589, but it was always rather poor as a through route due to the excessive running time. This was particularly bad southbound where a scheduled 10 minutes in Todmorden Bus Station was often nearer 15 - fine for me as a driver starting a mealbreak or finishing a shift, less good for through passengers, of which there were really very few at the time. Of course, there is now an option via rail that closely shadows this route, but both stations are fairly remote from their town centres. I'd be very happy to see the 589 return to give two bph from Todmorden to both Burnley and Rochdale, but I'm not holding my breath!
I'm not sure how much justification there would be to run via Bacup, which would duplicate the 464 Rochdale - Bacup and presumably replace the 8 from Bacup to Burnley? Rochdale to Edenfield is a long-lost link I agree, and scenic to boot, so maybe a Rochdale - Edenfield - Rawtenstall service might have some merit, but I doubt extending it to Burnley would add much.