Nonetheless, an average AF fit will out-survive and average destroyer fit...and should. AFs are T2 after all, and glass cannon is not their primary role. You could make a glass cannon AF but I personally wouldn't want to.
A destroyer's role is to fit as many of its high slots as possible with guns and melt t1 frigs and drones. (A wolfpack of them is not a bad match, DPS wise, against larger ships.) To do that it has to be able to mount decent guns without being cramped for power/cpu, something that in the past has been hard to do (8x 125mm rails with fitting skills at 5, I don't think I could manage without cpu/power mods, and 75mm rails are/were pea shooters), and they need to be able to catch what they're shooting at (also something that was hard to do).