I wonder though if the reason for the "save the cheerleader save the world" mantra is because if Sylar gets her power he will be pretty much unstoppable.

not true, if she dies while having something still stuck in her like a stake through her heart and out her back she wont revive untill its removed. So basically keep him like that and he will be dead.

Yeah but first of all they don't know that and secondly what are the chances they would do something like that. Most likely they would shoot him or the like and that would heal. He would be very ...

bullets would have to be removed to heal i believe, if they hit his heart they have to be removed for him to heal so technically not invincible

I never said invincible. lol. I said near unstoppable because now with his hearing anybody sneaking up on him he would hear and then ability to stop the bullets with his telekinesis.