Then, whenever anyone DOES die for real, the audience is sitting there scratching their heads like 'wellllll I don't buy it... you can just bring him back to life, after all, so why don't you?'
That's the huge problem with introducing those god-like abilities in. It's one thing when you can shoot fireballs or control the weather or something, but it's another when you just can't die or you can bring anyone back to life whenever you want. It's just like in the original superman where he flies back around the world fast enough to reverse time and rescue Lois Lane... yawwwwwn, who wants to watch any show where you know that the protagonist can just reverse the flow of time and save it?
That's why I liked Hiro's ability in the beginning - he was so worried about messing up the time space continuum (whatever) that I thought the writers would use that to limit his abilities. Instead, they've just let him go crazy with it. Nip/Tuck, anyone?