The Haitian can take away memories and knock people out, so his power might be broader than we think, general mind-control type thing. However, the idea that HRG is actually the power dampener is very interesting! Was he there when the Haitian and Eden stopped Sylar, though?
I think it would be nice if certain humans remained "ordinary", it creates interesting character development possibilities. As in X-Men, how do norms react when they learn that some people have super powers? I'm personally hoping Linderman and...oh, I can't remember his name, the Indian guy, remain powerless. Also looking forward to Linderman's ultimate unveiling.