Note scoring not offensive. I say u could argue Rose, Paul, Westbrook and Deron. Imo Westbrook if ur looking at pure scoring. He's now the most explosive and athletic with a wicked mid range pop. Rose won't be as great IMO when he returns and Paul/Deron are more passy.
Deron williams would be my best scoring Point Guard, he is like Carmelo, can shoot anywhere from the field, he has the size to post-up smaller guards,
Westbrook, his Game 4 Finals performance was amazing.