The only thing I dislike about the Sovereign class is it's limitations for deep space exploration. It's not exactly a ship designed with exploration, diplomacy and scientific discovery in mind. Mind you, neither was the Galaxy class, although there was something friendlier about the Galaxy class design.
The Sovereign could be equipped with all the facilities needed for deep space exploration, but at it's core it's a tactical cruiser built to take a pounding and put up a fight. The sleeker and more muscular design of the ship compared to the likes of the Galaxy class, speaks volumes about it's function (add to that the darker internal design).
Starfleet should build a class of ship that has the scientific facilities of the Nebula class, the fortitude of the Galaxy class, the speed of the Intrepid class and the firepower of the Defiant class. I mean the Prometheus came pretty close, but it just isn't big enough to house a regular crew compliment along with the facilities needed for a ship of exploration.