I see. Thats fair enough, but I still would like to see the new skins. (I just want to see the new Odyssey skin. I hope its epic and does the new bridge justice)
Obviously I don't know for certain, but I have a feeling these 'skins' are only going to be very minor changes - like, making a more definite line to show the Odyssey has Saucer Separation as well as the addition of the small Aquarius escort attached to the ship, and as for the Bortasqu', the tip of the detachable Bird of Prey will be visible on top of the ship etc . But this is just my opinion and I hope I'm wrong. :p
However, this would make sense as to why the new skins are not interchangeable with the standard Odyssey and Bortas.