Well no, I don't deny his impact on contempory music. But "historical figure" is something that can't really be judged, in my opinion, by contemporaries. It will take the test of time (and I don't mean the Civ II release!)
Will he be well known and highly regarded in his field in 200 years? 400 years? Maybe, maybe not, but for now I would just say he's just a singer/songwriter.