Many ships in WC canon come from the novels (primarily by William Forstchen), but were never seen in any games, and therefore there are no WC graphical references to base them on. However, inferences can usually be made. For instance, if a space interceptor was seen sitting at Johnson Island's spaceport in McAuliffe, it probably means that the ship was capable of taking off from the space port and flying atmospherically to high altitude and then propel itself to orbital velocities. A ship of the shape of a Broadsword could certainly NOT do so. For a ship to fly up to orbit it has to be able to to fly at high Mach numbers (supersonically) and therefore must be long and thin, have sharp leading edges and swept wings. Conversely, if a ship is said to be a “pure space interceptor”, it means that aerodynamic concerns don't apply, and that the ship would be optimized for space-flight propulsion and maneuverability: Large ion engines, maneuvering drives mounted on nacelles away from the ship's center of inertia, lots of greebles, and armor plates wouldn't have to match smoothly either.

Furthermore, keep in mind that the original creators of Wing Commander based their ship classes names on ships in the real world, and their ship's shapes often resemble, esthetically, their real world namesakes. Take the WC's Thunderbolt heavy fighter for an arbitrary example:

Here's a real-world Thunderbolt (refueling):

Notice a bit of resemblance?
It makes sense, in game production, to base the game universe

to be continued…