Some things are never as simple as they first look!
BMI is not that lucrative an acquisition for LH. They wanted it in 2005 but now it is a corporate millstone. LH have just had their stock rating reduced to junk.
First BA would have to relinquish alot of the BMI slots but, lets be honest, they would drop those routes which clashed with rival BA SH flights so the potential 'revenue loss' would be minimal.
In the current climate where LH are buying up rivals throughout Europe whilst operating with 75-80% slots out of Frankfurt the ability of BA to acquire BMI is, probably, not too difficult. Despite the problems BA still have the cash to complete the purchase and, given the value of the LHR presence, could raise further funding if required. Add to that the ability to negotiate with destination airports to provide arrival slots which tie up with the departure slots from LHR to give fuel efficient flight times and you have an enticing business package.
What do Virgin bring to the table? SA want rid of their 50% and the airline is struggling to keep its head above financial water at the moment.
Whatever happens, I truly hope that the crews at BMI get a fair deal at the end of the day, whilst the managers might view us all as statistics at the bottom of a spreadsheet we all know better.
Good luck.