@Embolish
Interceptors aren't exactly the most well-armed fighters - usually they've got a large number of lightly armored craft in their wing, but only one or two weapons per fighter at most. The Talon and Sparks are incredibly OP right now, even Alex admitted that (and nerfed them), so leave that out of your calculations.
They can be used offensively or defensively, in any anti-fighter capacity, which is fitting.
Assault Fighters here pretty much take up the role of anti-ship fighters that aren't dedicated bombers. Lots of armor, heavy ordnance (for a fighter), and possibly something else. Currently the only Assault Fighter we have is the Warthog, so we can't really tell what the "possibly something else is", as the Warthog's is flares -speaking of, if you ask me, the Warthog is a tad bit OP because it takes the dedicated Heavy Fighters flare and simply walks with it while being better in nearly every respect. Single flares would probably be better, or a different ship system entirely.
Heavy Fighters aren't exactly the best at taking down ships; the Lux, Broadsword, etc. don't have much stopping power (though they do have more firepower per fighter than Interceptors) -
Warthogs have a definite advantage over them with triple Light Mortars on each craft. Their main role, far as I can tell, is to take hits and attract attention to make way for the bombers. Reasonable and venerable role, if not a tad bit dicey for the pilots.
Speaking of the Gladius, I think it's intended role is (as it says on the tin) to be an Interceptor - but not just any, a Heavy Interceptor. I'm assuming here Alex intended the single-use flares on it to be deployed when engaging a group of other Interceptors so the flares attract their weapon's fire (which are usually PD) while the MGs and IR Pulse Lasers eat into them. Very, very niche (possibly too niche - only works against other enemy Interceptors), and though I haven't tested it, I don't feel it would be very effective. It needs a change.