Olaf Needs a Nerf (at least in ARAM)

Just played a match in ARAM against an Olaf that literally tanked 2 DPS and killed our 2 tanks (malphite and cho'gath). Not saying his team didn't help, but his effect was so great that him being in the fight was the difference between who slaughtered the other side (not a close fight, a one-sided stomp - all determined by one player).

Please, either nerf his regen, reduce his damage output, or give him less health. Is he an ADC, tank or Bruiser? Right now I can't tell.

Keep in mind, this is only talking about ARAM, as I don't actually know how his Summoner's Rift build may change. But maybe he's a bit too strong there too? I couldn't say, but I can imagine it based on his ARAM survivability and damage output; it's like a Vi with 200% lifesteal (I'm embellishing here, it only seems like 200% lifesteal).