I think any suitable headphone, curveball or not, old or new should be considered.
The thing with classical music is that it uses the whole spectrum so ideally you need a flat sound signature or at worst one where no frequency overpowers another. I've not heard the P7 but read that its character is v shaped so it's probably not the best for classical in general. However Philips L2 is interesting because it seems to be more neutral and resolving than the L1 and other recent headphones so it could be in the mix.
Others that have been suggested for classical:
DT880, HD600 - recommended by professional musicians
DT660 - recommended exclusively for classical in David Mahler's thread
I am also intrigued by DT250-250 as it is said to have a neutral honest Beyer sound but without the midrange slightly recessed, more like Sennheiser. Sounds like best of both worlds.