Krafus said:
If the Haitian was able to block all powers, Nathan wouldn't have been able to escape him and Bennett by flying away when they cornered him.
As to Sylar, I also don't believe he can sense powers - otherwise he wouldn't have picked the wrong cheerleader, and he'd likely have gone after Hiro instead of Charlie (whom I'm now not even sure has a superpower).
All in all, although I agree this wasn't the best ep, I was glad to see Sylar's backstory. And the preview for next week's ep makes me hopeful it'll get back on track ('twas fun to see Sylar ranting).
Evil rants are always fun.
It's perfectly possible for Sylar to have sensory powers, but it depends on how the usage of those powers is defined. If he has to 'turn it on' and aim it at someone, that's very different than a wide angle passive scan.
How the turn-it-on theory can work:
Back at the watch shop, he subconsciously turned it on and aimed it at Poppa Suresh's watch. At the time, he didn't know he did it, or that he could do it at people's brains.
At the restaurant, he pinged the waitress, but didn't ping Hiro, who he had no reason to ping.
At the school, he already knew who the cheerleader was - Jackie. He saw it on the news. He was about to verify it it with her brain (after killing her) when Claire-bear fixed herself, and he realized that he had the wrong girl.
If it's passive, and always on, then you're right...it makes no sense.
I also note that we still haven't seen any other Sylar manifested powers. Does he have them, or is he merely eliminating other 'special' people?
I think that Peter vs. Sylar will be a continuing theme for the season. Both have absorbtion abilities, both have a sense of 'destiny'. We also have the care-giver vs the destroyer. Good stuff.