First thoughts: Sword made me think Leo, Mask looks kind've orange to me so Mikey, and the background is red so Raph. Why can't I see one turtle at a time? ^_^' Maybe cause I've been fangirling too much recently. Very nice detail, though. I like the style.
Yeah I have always thought making it that easy to identify which turtle is which could actually be more dangerous for them. "Quick every bad guy in ear shot attack the one in blue, he seems to be the one giving orders!"