Alright, let me give you some insight into what I made:
- I noticed that you had some Sovereign-like inspiration in the design.  Two things in particular stuck out - the dorsal engineering hull has that bulbous area, and the rest of the engineering hull has a similar Sovereign-like shape.  I kept both of these hints, but added a few more.  I don't like to mix eras, as it doesn't really make sense.  When engineers are designing largely for function, retro-parts aren't a good choice.  Therefore, you can see I added Sovereign-like nacelles and redefined the dorsal saucer exterior, including the impulse engines.  They're in the same location, but they're more like those of the Sovereign class.
- However, that no-retro rule doesn't really apply to the overall shape.  As you can see, I kept the same proportions, more or less.
- I reduced the fantail to a more functional shape.  It can serve both as a surface for phasers, like on the Galaxy class and Sovereign class Nemesis refit, and as a sort of "runway" if you will for the aft shuttlebay.