Bzzzt. The constant in sushi is cooked vinegared rice. The other ingredients (neta) can vary and don't need to include raw seafood.
YOU are exactly right! In Japan, it is ALL about the quality of the RICE!!! The use of a Mirian type of sweetened rice wine, like Kikkoman Manjo Aji-Mirin wine, in the cooked rice is one of the best! Thanks for pointing this out!