Yes, not much cooking aside from some specific items like abalone, shrimps, eel, .... but it takes just as much skill to be a good sushi chef as any other types of chef. Think fish selection (sardine season now in Japan so which port has the best sardines?), aging (most fish are aged for a few hours to a few days), rice preparation (which type of vinegar and which type of rice, some chef use different types for different fishes), fish cutting (which part to serve and how to cut, how thick and how large), course progression (which piece first?), seasoning (shoyu, wasabi, ginger, scallion, shallots, ....), .... There are so many factors going into fine dining sushi!