It's too short and stumpy to be a Capship IMO. Have a look at the shivan fleet. They don't have a single canon ship in that sort of configuration. It'd maybe work as a sort of uberfighter or bomber, or possibly as a nightmare cap, but not a shivan cap.
The uberfighter might be the most interesting of all actually. A wing of these show up, with hitpoints and shield values greater than that of a seraphim, but with the speed and manoeuvrability of a Manticore. The ultimate Shivan vessel. You'd balance it through scarcity and storyline rather than making balance intrinsinc to the mod itself