Big victory, maybe little gain
Remember the landmark US Supreme Court decision that ruled foreign cruise lines operating in the US had to follow US accessibility standards? According to this article, the US Access Board hasn't issued any guidelines to said cruise lines. So it's likely little progress has been made. In other words, you'd better still check out just what accessible means on a cruise ship. Some very good food for thought in this article as well about what details you might want to nail down before taking a cruise with a wheelchair.