I though that with imperatives, you generally dropped the "-en" suffix from the verb's infinitive form. For example, the imperative form of "gehen" is "geh". If that's correct, wouldn't the imperative of "sehen" be "seh", rather than "sehen"?
Schauen means "look," sehen means "to see" and "to look." Schauen has more connoations with something being displayed, imo, as die Schau is something that is put on to be be viewed--a display, an exhibition or show.