Centre Cities,
I base my reasoning on contact I had with Air Transat some months ago, when I asked them if they would add Vancouver and Calgary in 2014 to BHX when our runway extension would allow.
Also if they would add another YYZ as we had a 97% load factor on an A330 last year..
The gent replied these was not in their plans for 2014 and BHX was lucky ,as it was their only UK airport with just 1 flt and destination, and therefore operationally it was more problematic.
Nigel