The similarity between the overall layout of B'Rel, D7 / K'T'Inga, and Vor'Cha is pretty close - all have a forward section with the bridge and some weapons, including a torpedo launcher, all have the connecting neck to an engineering hull, all have wing like structures attached to the body. The B'Rel does depart from the norm somewhat - almost every design of ship we've ever seen has the warp engines located in nacelles held away from the body. Yet the B'Rels wings are tipped with disrupter cannon, and its warp engines are inside the engineering hull itself. The most obvious explanation is that the B'Rel is designed for atmospheric flight. The wings are occasionally seen to move up and down for this - to vary their geometry, not to flap! One could say that the Klingons couldn't work out a way to pivot the wings while having heavy duty plasma transfer conduits running through them.

The nose carries a torpedo tube which we've seen fire various times. In ST III Kruge was informed that his ship was "ready to fire emergency tube" after it took a couple of hits from the Enterprise. I've never seen any evidence of any kind of aft facing torpedo tube such as the Vor'Cha or K'T'Inga has.

I imagine there have been large numbers of different sub-types of the B'Rel class - possibly even hundreds, given the amount of time they have been in service. At least some of these have their own separate class designations - as with the D-12. My guess is that this only applies to ships that are fairly radically different to the standard B'Rel - this isn't based on any evidence, I'm just reluctant to write endless variations of the B'Rel page for every ship we've seen. As a result, I've got Martoks ship from the latter seasons of DS9 classified as a B'Rel, even though it's somewhat larger than the normal ships we've seen.

The various roles I've described for the B'Rel seem to be in keeping with her size and capabilities.