We are here to assist others and not give horrible advise. Just because a few cpus would be "ok" without paste doesn't mean you should ever suggest not using paste and potentially cause issues for them. Even if temps don't get to shut off temps, there is no reason to run a cpu hotter than it needs to be and trip prochot. The h100i is convex and so are many modern cpus so that's not a good contact area without paste. Older cpus like 775 are concave and many other coolers are convex so would fare better. If someone is getting an h100i, they probably aren't using an old or low end cpu and they probably want to be more careful with expensive hardware.