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Another viewpoint on BCS theory is to consider that the boson has an inherent energy which is lower than the fermi level. It seems reasonable to suggest that the boson will remain stable until there are a pair of available energy states in the fermion density of states(DOS) of energy equal or lower than the boson's. Thus as temperature rises the availability of empty paired states occurs further below the fermi level, until it can provide exit states for the boson's constituents.
The maths of BCS should equate to the fermi-dirac distribution for paired states.

The reason the HTSC fling BCS out the window is because the inherent energy of the boson lies inside a semi-conductor bandgap in the cuprate DOS. Thus the critical field/temp. graph for the cuprates follows BCS for the first 10K or so until there are vacant states at the top of the semi-conductor bandgap (Energy vertical on DOS diagram). After that point the only way for the boson's energy to reach the lowest exit states is by its own thermal energy.
So BCS thermal breakdown may be characterized as lower fermion exit states described by fermi-dirac statistics.
By analogy, HTSC thermal breakdown may be seen as the boson increasing its own thermal energy obeying Bose-Einstein.
Since I'm sticking my neck out here, may I suggest that room-temperature SC will be achieved with single-walled carbon nanotubes with metal inside set at low density in an insulating bulk.
sandy@zymandia.com