As kitschy and saccharine as they can sometimes be, there’s absolutely nothing wrong with the concept of a love song, and for the most part, there’s certainly nothing wrong with one written by Sir Paul McCartney of all people. Perhaps the most prolific purveyor of the form both during and after life with The Beatles, Macca’s most amorous tunes almost always come from the heart, and while some of them have been the subject of derision from critic…