I can understand some peoples frustration with the BBMF,but as I have mentioned in previous posts it is just down to bad luck with the weather mainly.
Portrush as just been unlucky and has had more than it`s fair share of no-shows from the BBMF.
The BBMF operate under VFR rules,and also the aircraft only operate very restricted flying hours:as far as I am concerned the BBMF are very special and it is a real treat to see them. 
I am a big fan of warbirds;the only thing I don`t like to see is the Swastika 

 displayed on some German WWII types (it is still illegal to display a Swastika in France).
Historical accuracy is normally the excuse,but some operators of German WWII warbirds have just a German cross on the tail,or nothing at all. 
Personally I love the sound of the Rolls Royce Merlin engines;with the BBMF if they manage to make it you have 6 of them at once ( FANTASTIC!!!)  
 
  
  
  I don`t think an airshow is complete without a few WWII aircraft,but I agree more variety would be nice. 
Having an airshow at Aldergrove or Belfast City (or any UK commercial airport) would be almost impossible now because of the security implications.