Well, Puddicat, I don't usually like soul singers of Aaron Neville's ilk, but was taken with this from the moment I heard it in the film.
This version is a 'classic', as are many contemporary ballads (I Will Always Love You is a debatable classic), but what I think you mean is that soul balladeers like Neville should stay away from 'classical' songs (ie. 'art' music, generally speaking). I guess what you also mean is that you prefer classical songs to be sung 'properly'. Bit boring, that. Music is there to be explored.
The girl on BGT sings very well, certainly better than I can, but there's no 'spark' in her performance. She doesn't seem to be exploring the piece or putting her own 'take' on it.