My first character is a Science Officer and was hoping to be able to dish out some serious damage further into his career but looking at the comparables it seems that the choice for a DPS based character/ship combination is a Tactical Officer + escort class ship... Correct?
If so, that would suit me fine as my favorite ship from the various series is the DS9 Defiant.
Also, are escorts really that much more maneuverable than the Miranda class ships or does improved maneuverability have more to do with increasing the character's skills and the ship's equipment?
The Miranda class has a turn rate of 11.4, while the Defiant has 17. Comparatively, the Defiant turns on a dime while the Miranda does a 3 point turn in the parking lot. Unlike the Miranda, the Defiant's stats were built with cannons in mind. While the Miranda can use cannons, the lower turn rate makes it much harder to get into the 45 degree fire arc that the cannons have. The Defiant has zero problems doing this.
You may want to take a look at the mvae as well as it can help complement your sci abilities. It is the only escort with a lt commander sci boff station. The mvam with photonic fleet and scorpion fighters can be good for spam.