The F70s are being replaced with E175s. Expect the route to continue on E175 and upgrade eventually to E190. KLM are strong in Asia and must be making a killing with all the Asian students that study in Southampton.
In terms of BMI, I flew the Munich route in July and I counted 29 odd people. This was before BE started on the route so not sure how that is affecting them. On the way back most of the other passengers in Munich had Lufthansa tickets so they must be benefiting from that. The lady in front of me was routing from Greece. It shows how much of an advantage code sharing with a big carrier can be. Personally I hope BE stop serving the route and all this teritorial nonsense. They have a history of pushing other operators out of SOU and then stop serving the route a few months later. Brussels anyone?