To answer a few inaccuracies.
The bus was with one company but is now a Yellow bus and is a direct route to the train station/town centre, gone is the route around the hotels. I'm sure that if there's more demand then capacity will increase. (business agility)
The departures terminal is bigger than Southampton's and was designed to handle up to 3million pax. Not sure about the arrivals. As for a business lounge, I'm sure something can be built within the existing facility.
Car Parking could be difficult though, but I'm sure BOH have plans to create more.
But I can't see it happenning, I'm inclined to think along the same lines Markeyd in that Flybe are holding out for a better deal with Southampton. And I doubt they would be happy to lose their (only) customer.