The wording of the question outlines their real problem.
You say "role". What is an AFs role?
As far as I can see their role is to be highly effective at frig PVP and they do that OK... however they don't really need a 4th bonus to do that.
Just by virtue of having more HP and more DPS they're already better than a most other frigs for combat.
That's cool for 1vs1 or possibly frigate gangs but in any normal gang you can achieve the same thing cheaper with an insurable T1 cruiser. Also note that a T1 cruiser tends to come out ahead.
An intie by comparison fills a particular niche in gang PVP.
You can say the same about EAFs too (T1 cruisers do the same but better and cheaper).
I don't honestly know what you do to AFs to make them "better". I just don't think they fill a hugely needed niche in EVE.