The annoying thing is the designers are still around and they would gladly come back to design ships but they refuse to hire them. The only guy around still is John Eaves and his work barely makes it to the show. I think the last time we saw one of his ships was in episode 1 with that Romulan scout ship.
EDIT: Actually the 2385 shuttles were his as well.
Other than the La Sirena and the ancient Bird of Prey, I’m pretty sure Eaves designed all the other ships, unless you have a source that says otherwise.