Heathrow is very slot constrained so probably not a lot of extra flights especially in morning as it is already so busy but I can see American and BA moving flights over from Gatwick.
I thought Manchester was not really affected by the Old Bermuda so not sure if it will have a vast effect
Places that could do quite well are Stansted and Luton in my opinion
Heathrow is slot constraint now, but with T5 just around the corner, and a most likely 3rd runway and another new terminal, there should be a big change! (Obviously not immediately!)
Why would BA move flights to LGW? LHR is 'theirs.' No airline comes close to what they operate from that airport. If they sacrafice some of these slots, they are basically giving BMI the chance to move in. I suppose if they were to move the US flights to LGW and start new East Bound services, that could work.
Manchester is throwing itself into a massive expansion plan for 2015. They want new services on long haul routes. This could help them, as the LC airlines may get involved.
I definatley think that LTN would grown rapidly, but STN just doesn't have the space at the moment. They are nearing their maximum capacity of 25 million pax per annum. I think that the airports to watch are LPL, NCL and EMA. Big with the LC carriers, and could be the bases for the next revolution in air travel.