Like Intrinsic_ said earlier in the topic. Armour tanking when used by players is overpowered. Toggling shield only for a fraction of a second to stop a heavy mauler shot or torpedoes means you will win the flux war every time. The problem is armour is not useful in AI hands as they don't use it to its full potential.
That's why that hullmod from a mod that removes shields from ships is overpowered when put on AI ships.
I feel like this whole thread can be simplified into either (A) AI don't use armour to its advantage thus armour sucks. (B) Armor should stack better when going into extreme values, though only really applicable to onslaught or stations.
Armor/hull tanking is exchanging the ability to negate damage for the one of shooting more and generally being more aggressive. Shield Inhibitor (from Ship/Weapon pack) permanently disables the shield for 50% better base flux dissipation, meaning you can install more flux intensive weapons at the cost of heavily, heavily investing in point defence, repair rates, emp resistance and hull hitpoints.
The one thing that prevents it from being OP as far as I'm concerned is simple: it either works wonderfully or fails horribly depending on the size of the ship it's done on and the situation it's in.
Example: My Prophet is the biggest ship in my fleet at 50FP. It has 330 base ordinance points, going up to 363 with skills
-Shield Inhibitor is 10OP (easy enough) but then comes Automted Repair Unit (15OP), Resistant Flux Conduits (15OP) Reinforced Bulkheads (30OP), Solar Shielding (15OP) and a mod Modspec called Integrated Armor (30OP) doubling the residual armor value from 5 to 10% up to 200 on capitals(you can probably use Blast Doors if you don't have this, it's 25OP instead of 30 too). So that's 115 Ordinance Points just to not have it die horribly to just one Onslaught saying Laser go brr.
-It needs 8 dual flaks and 16 small AA weapons plus point defence AI to make sure not one missile taps it and makes it retreat crying for mommy (that's 138 Ordinance points) meaning that one think of my flagship is dedicated to just defending itself against missiles, fighters, mines and bombers.
-As for weapons, the ship has Heavy Weapon Integration to fill those 4 large mounts (2 energy and 2 ballistic, I'm going to use 4 ballistic) but we're going to need even more modspecs for the weapons like Integrated Targeting Unit (25OP) Particle Accellerator (10OP, increases projectile travel speed by 35%) and Weapon Inhibitor (25OP, Reduces ballistic weapon flux generation by 20%, reduces ballistic weapon rate of fire by 10%) and then install some decently flux efficient (and flux intensive) heavy mounts and voila, there's the whole 363 ordinance Points spent
If you've painstakingly read this whole description, you'll realize I did not even have OP left for vents. The Base flux dissipation is now 1600 and the ship firing all of its weapons at the same time eats a whopping 3692 flux/second (3692*0.8*0.9 equals 2658 Flux/second with Weapon inhibitor) meaning the ship with its 20880 flux capacity can only fire for 20880/(2658-1600)=9.73 seconds before going max flux and having to throttle its weapons down to not overload.
This is of course with an officer improving energy capacity and dissipation. The situation it a lot more dire without one but I decided to make the calculation with an officer since I don't see anyone using a 50FP ship without one.
The result is an incredibly resilient ship, almost virtually immune to bomber and missile attacks but that has rather low weapon range (for a capital) with its max range clocking in at 900 units but very vulnerable to hammer and anvil tactics involving a generally resilient ship being supported by smaller, damage dealing typs ike Sunders/Atlas Mk.2s just to name two Vanilla threats.
It will excel and I really mean excel, doing something like 600% damage (with its massive 35k hull hitpoints constituting the 100%) in fighting one slow enemy after another since two of its weapons are basically Kinetic/EMP scattershots and the remaining two are very efficient, 700u range heavy autocannons but it will really struggle with anything above a fast cruiser since it's just a hunk of metal moving at its 22 top speed with brief (Tyrant Microburn levels of movement) bursts of agility and speed thanks to its special ability.
It's like one of those clunky womanizers really, really good at going in (forgive me, could not resist) but having a lot of trouble actually disengaging once the situation comes dire and there's something like a Piranha Legion squaring it in her sights and going.
Tach lance Radiant at 0:38 
Also, keep in mind that the Prophet is basically the non-plus ultra for both stock armor and HP that's generally widely avaiable, XIV Onslaught is close but does not have much OP to install everything. Any other ship trying to do this king of low range no shield tanking is going to die horribly. Trust me I've tried. What on the other hand works is cruiser or even battlecruiser sized ships with very good frontal firepower playing the kiting game. The double Gauss Cannon XIV Dominator does really well without a shield just to name one.