It does not need to be a nerf, if the tuners are buffed equally but the stacking is penalized. Therefore by the 3rd or 4th tuners you will be thinking if its worth the slot wasted or maybe add something else instead.

What is going to happen when we get new bots with 10 head slots then? Sooner or later it has to happen.

Not saying I agree. But if the devs did do something it would be best to do it with: http://en.wikipedia.org/wiki/Diminishing_returns

Please do not make any more unique modules like lwf or only X number can be fitted.

Yeah like why is a geoscanner unique?

I vote NO to any nerfing of module stacking. 

Fully stacked head slots with the same module usually only performs in a nitch roll and is easily countered as there are many weaknesses to exploit.

NO to stacking nerf, keep variety.

I'd agree if they hadn't built the system from the top down.

I have a Thelodica Mech agent with 300K EP all of it tied to making the Agent a good Thelodica Mech agent. That's a 3 month effective character with a single purpose in the game and she needs minimum 15 volley to kill a 1st star, T1 Kain NPC. If I am running her solo, she then needs another 15 minutes to rep off the damage and recharge Accum and be ready to clear a spawn a second time. I am averaging 20 NPCs (800K worth of plasma) an hour.

The fit is Meta 2 with 2 tuning and 2 senor amps. In truth the repair time, it's faster to go to an outpost and dock, deploy if there is an outpost closer than 6000 meters, it takes that long to repair and recharge accum with low EP.

When they made this system they expected us to stack damage. 450% might seem like massive buff but it's buffing from such a low base that it's only balanced when it's extreme stacked.

It's pretty interesting idea and can easily be modified to not suit PVP while work in PVE, but I personally think that the game just flat out doesn't need a mod like that right now. Give us harder NPC and we should come back to something like that.