Having read the edit...
While I agree with you in principle, I really don't like the idea of giving certain players an advantage because of their hardware. While I doubt many would have enough computers (or desk space & KVM switches) to reasonably manage the number of alt accounts we've seen recently, even having control of two characters at the same time can put someone at a significant advantage over everyone else. I've been in a game like that, and the players with "mules" really skewed some of the end-game competitions into giant popularity contests.