I agree the Steamrunner, Ambasssador, and New Orleans are at the top of my list. Not to sound like a broken record but I would MUCH rather have more cannon ships then more STO designed junk.
Although I'd love a T5 Steamrunner I have to say I can't agree about the 'STO Junk' any more. Some of the early Cryptic designed ships were horrible (like the T4 Galaxy skins) but some are very nice. Ships like the Star Cruisers, Venture, Maelstrom, the upcoming Intrepid and Akira variants aswell as the KDFs Vor'kang and K'Tinga refit (I can't remember the actual spelling) are very nice and IMO much nicer looking than some of the minor canon ships.