Olaf was once a very staple pick and very overpowered in the sense that he could assassinate while building extremely tanky. Though this was true, this was also in a time when HP recipes were far too cash efficient, meaning Olaf could build the "best" defensive items and deal devastating damage during this golden age (Sunfire Cape, Warmog's Armor, Randuin's Omen.)
With that said, the beloved viking doesn't have a strong niche anymore as he no longer instills fear in the enemy AD carries and instead is easily kited or killed due to his weakened steroid abilities. Riot doesn't want to simply revert Olaf to his pre-nerf status, as it made him strong though he may be a lot more tame with the current set of item statistics. Riot would rather take an entirely new approach -- so we may be finding ourselves a new playstyle on Olaf.
Though no details have been unveiled for the fate of our old viking friend, past evidence would conclude that Riot will most likely stray away from his natural damage stats in favor of making him naturally more vulnerable for building damage, similarly to how they are addressing other melee carries such as Master Yi, though only time will tell.
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