Ok, is it just me or is Sai's jutsu's potential completely wasted? I mean, okay, don't get me wrong, Sai is quite strong as he is, but I feel like Kishi is limiting his potential by a lot. If he can draw things and make them come to life then he can do most anything, not only power-wise, but also intelligence-wise. We only see him using 4-5 drawings maximum. Is there a specific reason for his limited 'repertoire' that I have missed?