in my lowly opinion it has to do with GOOD DESIGN.
constitution and sovereign classes are really bad designs from a realistic point of view, i.e. the bridge is a hood ornament, lightly armoured and in some cases no defenses. While the new battlestars are a feasible design, command and control is in deep and protected plus there are batteries and batteries of ship-defense systems ranging from the phalanx type to just plain old cold rolled steel, albeit 74 inches thick but by golly is works.
also PROPORTIONATE REALITY. yeah i said "UH?" when it first popped into my head, this is a real simple principle though. basically it applies for modellers and it just plainly states that what is designed must be proportionate to what is designed. So you can't have a 20,000 meter long ship with eight galaxy class warp nacelles two saucer sections side by side and refer to it as a "Heavy frigate".
lastly, ORIGINAL CONCEPT. Wicked Zombie is good at this so is TUS with his ICON and McCOY Classes. Whoever came up with the Kryptonian PREUS Class and whomever designed the Hellions, that was very original. Now better textures for the Constitution Class are always welcome but you can only take the "ol girl" so far as meshes and kitbashes are concerned.
These are just my own opinions. They are not meant to belittle or show favoritism to anyone.
I have though the patent and trademark on the term "PROPORTIONATE REALITY" and it's definition. Just like Bill does on the term "WINDOWS" when applied toward computers and/or the programming, development of programming and/or software for computers and/or the programming, development and development of software and such.