Oh get real. BA screwed PIK in the 1960s and 1970s, and similar in MAN objecting to every application from competitors. This is 2008.
BA have almost gone and MAN now has better options to connect to the world with the US carriers and the Middle East airlines. Who exactly do you guys expect to operate into MAN that you don't already have? You have all the major long haul you're going to get I think, a fine network it is too.
BMI never wanted to fly long haul from MAN, they made the best of a bad deal when they lost the chance to base them at LHR and had 3 A330s and nowhere to fly them.
The last new jet BA brought to MAN would be BAC111 G-BGKG in the early 1980s!! Everything since has been second hand or a LHR hand me down.
Maybe if there was about 7 flights a day by both BA & BMI, Then it would give MAN the chance to send it's pax direct on other potential flights
A lot of business travellers fly BA for the BA Miles, BMI users are STAR Aliiance customers who have loyalty cards a lot of the time. Removing that option is your idea of boosting business from MAN?