They've already talked with the creator of the Vesta class, who actually wants them to use it in the game and Capt.Logan has mentioned that we will get it, eventually. They just have to deal with all the problems with CBS.
The JJ Enterprise is a much bigger issue and would be harder to explain in game.. I think it'd be a fun little bonus, if they could find a way. But yeah, don't hold your breath. Buy the Exeter instead, it's a great little ship