Granted, I haven't tried this in a long time, but the first time I did try it, nothing happened.
I made my Runabout my Active Ship and clicked Visit Bridge.
Surely it wouldn't be too hard to make a Runabout interior?
I mean, they're not a very big ship, basically, just a small command module, a bridging section and the cargo hold towards the rear of the ship (a Runabout is basically a flying cargo module, the cargo hold comprises most of the the ship).
And they should make a Delta Flyer interior when that ship comes out as well.
It's somewhat larger then a Runabout, but it's still a relatively small space compared to the larger vessels.
If I had to pose a guess, it's because the devs figure that as they have to make bridges so big to allow room for the camera to move in them, that the feel of a Runabout's cramped interior would be lost when scaled up to the size of an in-game bridge.
That said, I'd like to see a "bridge" for a Runabout, which would basically just be a floor plan of the thing. Two consoles at the front, a transporter, and a section in the back for the engine room. Bonus points if they can actually make it so it looks like you're realistically looking out at space through the windows.
They most definately shouldn't have a Layout selection in the customizer, since they don't have decks.
I'd love to see a ship interior for shuttles. One interior for every kind of shuttle would be enough, though. It does not have to differ between different types as the differences would not be extreme, and given how we can't even get accurate bridges I do not believe we'll get accurate shuttle interiors anyways. Also, as has been pointed out, priorities.
That said, I'm kind of worried as to whether it is even possible to create a shuttle interior, given that Cryptic seems woefully inable to do "cramped" spaces. A 10mē hallway bridge for a shuttlecraft would look really weird. :/