When thinking about T Swift and whether or not she's great, comparisons like Bob Dylan are not really appropriate. Dylan wrote some pop, but that's not really what he was about, so it's not the same thing.
I think Swift is great, but in a totally different way. Sure she started out in the "country" universe, but she's really just part of a long line of great pop artists. Michael Jackson is the King. Stevie Wonder is one of the best ever. The Bee Gees were one of the best.
Who are the other greatest pop artists of all time? I'm looking for great pop to listen to today.