Re: Constitution, Miranda, and Constelation Class
I wouldn't call it a failed design, but TPTB have always been weird when it comes to how they use some models. There was only one Intrepid class vessel seen on DS9 (or outside of VOY for that matter), because VOY was still running then and for some reason they don't like to use other ships of the same class as a protagonist ship. I don't think it makes much difference to viewers myself.
"My dream is to eat candy and poop emeralds. I'm halfway successful."
Catbert, Evil Director of Human Resources