Although I realize it is technically wrong, I often draw comparisons to naval combat when thinking about potential combat in space between starships.
While you can compare a capital ship in space with a capital ship in the seas and the same can be said for fighters/starfighters, I find it difficult to imagine something similar to a chopper or a helicopter, which has a great many applications in modern times, even on sea.
As far as I'm concerned, a fighter/bomber/interceptor is a rapid reaction force that by virtue of its engine excels in any situation where speed or time is of the essence, and/or the terrain is wide open.
A helicopter, in general, is far more maneuverable and flexible (at the cost of speed) compared to a jet. This is most important in urban combat, but even on the wide sea a chopper can hold its position for an extended time, whereas a plane can't.
On the other, space is literally as open as it gets, so urban combat, unless we talk about "urban" being a huge starship, does not exist.
Now, with regards to comparing it to space combat: Would there ever be the need for a force that, like a helicopter, excels in maneuvering and holding its position, yet is more agile and speedy than any starship ever is, while being more flexible than a starfighter?
Do you see something like a space-helicopter having a role in space combat?
EDIT: ship maneuverability contrary to apparently popular opinion, fighters are more agile and speedy than capital ships, both in acceleration, deceleration as well as turning into either axis.
EDIT: in regards to tech - no individual FTL, but static in-system jumpgates. - laser, railgun, missiles are live - scenario comparable to Babylon 5 + BSG in regards to maneuverability and shiptech, FTL aside.
EDIT: To be more specific regarding the spaceships and starfighters
Imagine either a Babylon 5 Omega Destroyer or a Battlestar (Galactica) or a Venator SD as the capital ship and either a Starfury, X-Wing / TIE-Fighter or a Viper as the fighter/interceptor. Would there be a need or role for a unit slightly more massive than the fighter, but way, way less fast and more maneuverable.