If you eat Sushi on friday night or Shabbos Afternoon, it has the taam of shabbos it also has the taam of shabbos. Gefilte is a “food” created by people who did not know what real food tasted like
For those who must have fish on Shabbos and want fish without bones sushi is perfectly fine. We dont eat it in my house normally because its too expensive, but thats a financial issue, not a hashkafa issue.
There is also the bug issue. I’ve been told that some rabbonim don’t recommend all sushi, even under hechsher, because the seaweed doesn’t meet their standards.