Its been a while since i last read "feat of iron" however if i remember correctly the Eldar devised ways to nullify the iron hands augments, their bionic components were rendered useless and became naught but cumbersome liabilities, ironically it wasn't the flesh that failed, but what they replaced the flesh with (the eldar also poisoned Ferrus manus through his augmented hands.), my guess is the eldar used some sort of EMP.
furthermore, in a short story wherein a Raven guard and a iron hand work together to discover some form of intelligence (if my memory serves correctly) the iron hand was loud, slow and encumbered by his bionics.
also a quote from "wrath of iron":
they are not my hands.
This fact is forgotten by my brothers Ė inexplicably, it has always seemed to me. The hands are strong, to be sure, and have created great things for us all, but they are not mine. And that counts for something.
They forget that the silver on my arms comes from a beast that I vanquished. It is the mark of a great evil that I ended, and yet it persists within me. It is alien, artificial; an uneasy corollary to the superlative physical frame given to me by my father.
I would struggle to remove it now. The problem is not one of surgery, for I have no doubt my fatherís chirurgeons could remake me entirely if he gave them the command. No, I will not remove the silver from my flesh because I have learned to depend on it.
The fault is with my mind. I rely on the augmentation given to me by my metal gauntlets, so much so that the flesh beneath them is now little more than a memory.
It is a crutch, this silver. A day will come when I will strip it from me, lest I lose the power to master myself forever. Already my Legionís warriors replace their shield hands with metal in my honour, and so they too are learning to doubt the natural strength of their bodies. They must be weaned off this practice before it becomes a mania for them. Hatred of what is natural, of what is human, is the first and greatest of the corruptions.
So I record it here: when the time comes, I will strip my hands of their unnatural silver. I will instruct my Legion to recant their distrust of the flesh. I will turn them away from the gifts of the machine and bid them relearn the mysteries of flesh, bone and blood.
When my fatherís Crusade is over, this shall be my sacred task. When the fighting is done, I shall cure my Legion, and myself. For if fighting is all there is, if we may never pause to reflect on what such devotion to strength is doing to us, then our compulsion will only grow.
Already I see the madness that path leads to, and so I shall excise the silver from my hands. In doing so I shall weaken myself and my sons, but nonetheless it must be done.
The hands are strong, and have created great things, but they are not mine.
EDIT: however i should also point out im not trying to portray them in a purely negative light, they have their uses aswell, just trying to answer OP.
Last edited by Lost&Damned; 11-07-12 at 12:17 PM.