Im looking forward to the Hiro vs Peter showdown. Back in series one in the future episode where all mutants are hunted down by the goverment and Sylar is the president, didnt he have a scare on his face. IIRC everyone at the time questioned this as why would he if he can regenerate. Maybe fighting Hiro in Zerotime, he can get hurt and it not heal quite right. So thats how the scar is there. Therefore the future as we saw it then is still set in that aspect anyhow. So Sylar will get his powers back