Whilst general consensus is quite negative regarding BA pulling out of the regions, does anyone know how BA ops were doing at the time? If they were struggling to fill flights, is it any wonder they pulled out, especially given the growth easyJet and Ryanair were having at the time.
Since leaving Manchester, they've still had a limited presence through their shuttle service and through their JV with American, and more recently Vueling & Iberia.
Whilst growth at Manchester has been strong in recent years, has BA's reluctance to fly again from Manchester been due to the fact that other airlines already have a strong presence at Manchester. All the main destinations are served, and perhaps BA have felt there is not enough demand for them to add anything to what is already offered. Additionally, if BA moved into Manchester again, how would American fare? Do they have a particular interest in flying to Manchester or are they happy for BA to take over those routes?
I think a large part of BA's decision to remain London focused is due to the limited capacity available at London airports. Whilst some may say that should provide BA with a reason to look elsewhere for growth/opportunities, I think BA have been trying to maximize the efficiency of their ops from Heathrow and to a lesser extent Gatwick (particularly in light of the recession). This has meant that if BA felt that a 777 could offer better loads/returns operating from LHR/LGW than MAN, then they'd fly it from London and not Manchester. Now that a third runway at Heathrow looks more likely, perhaps that has eased the pressure on BA allowing them to reconsider flights from the regions, specifically Manchester.
Additionally, as new aircraft (B787 & A350) join the fleet replacing 777's at Heathrow, those 777's can be shifted to Gatwick allowing the older 777's at Gatwick to be used operating flights from Manchester. Likewise with new A320NEO's coming in and replacing A320CEO's.
That all may be rubbish, but just another angle to look at things.