Crosby, while a great player, isn't the best hockey player in anyone's generation. Gretzky would probably be no.1 unless you're like super old and got to see Howe play, but you know how arguing for an old-timer goes around here.
Read an oral history on the New York Islanders dynasty of the early '80s and most of those guys thought Mark Messier was a better all-around player than Gretzky, fwiw.