I just watched the game back (didn't go), and Smith's display was a joy to watch. Just about every kick absolutely on the dime, more repeat sets than you can shake a stick at, and he seems to have the the necessary instincts, passing and running game both look fine (I laughed when the Giants defenders backed off him, waiting for a kick, and of course he did exactly the right thing; take the metres on offer, draw and pass, draw and pass, and bingo, Marshall's over for his hat-trick). As for his defence, as Marshall has shown, to a large extent this can be improved by practice and hard work.
I agree he shouldn't be played all the time, and Tommy still offers plenty to the team, but we have some nice combinations brewing nowadays.