I actually have a crazy theory as well. If you read the Transcript of the Relic 2.0 specifications given to V by Anders Hellman, you learn that several attempts to use RELIC 2.0 to implant both a digitized engram and enhanced personality construct had resulted in failure. They had then attempted trials using subjects on the verge of biological death, but were still unsuccessful in activating the chips basic functionality. They then proceeded trials with hosts that had undergone both brain death and cardiac arrest. This also failed as the biochip would show initial signs of activating before lapsing. The question is why did the chip work on V, but no other test subjects. What was the missing ingredient in V's case that allowed the chip to function? My answer, serendipitous cross corporate synergy.
Let's talk about Sandra Dorsett, because she plays into my theory. When you return Sandra's databank to her you have a variety of options. You can choose to not read the databank at all. You can break its encryption and then lie about it. You can come clean and praise her, or you can come clean about reading it and attempt to blackmail her. Her reactions will span from paying you extra for your compliments, to attempting to gun you down with a home turret. I remember when I initially played through the various scenarios, her reactions seemed to go from 0 to 60 in a split second. Then, I remembered the contents of the databank.
Night corp was testing a AI designated CN-07 on its employees. The databank states how it had successfully bypassed various security systems and engage in a period of subliminal conditioning. It specifically notes how a subject that had been calm and empathetic experiences a psychotic break, strangled a colleague over a coffee dispute (which gets some empathy from me, I have often wanted to strangle coworkers that kill the pot and don't start a new one) and then throws themself out a 16th story window. So, the more I thought about it, the more it made sense that Sandra has already been experiencing the effects of CN-07 and when stressed quickly resorts to extreme violence.
Now, what does this have to do with V? Well, when V rescues Sandra at the beginning of the game, he has to interface directly with her system to get her vital stats. During this interface, he appears to pick up some kind of virus. He has Vic look at it the next day while getting new optics. Vic assures him he flushed it from his systems. But, my suspicion is that he did not, or that by the time he did, CN-07 had already began its process of conditioning V's mind.
RELIC 2.0 failed previously because even when implanted on test subjects that had undergone brain death, the brain itself still required additional conditioning to accept RELIC 2.0's programming. The RELIC would have only worked on V because V was one of the few people that was actually in a per-conditioned state that would prove ultimately receptive to RELIC 2.0's primary function.