So Gragas got turned into a tank because his poke and sustain were a problem...

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It doesn't really matter what he was "meant to be". His poke and sustain (and his mobility and disruption) were problematic. Riot reworks him into a tank, and afterwards he's pretty balanced. This same idea can be used to balance other problematic champs, like Ahri.

his poke and sustain wasnt a "problem" after they gutted him.

{quoted}

It doesn't really matter what he was "meant to be". His poke and sustain (and his mobility and disruption) were problematic. Riot reworks him into a tank, and afterwards he's pretty balanced. This same idea can be used to balance other problematic champs, like Ahri.

U are forgetting one thing about Gragas sustain. He didnt only have HP sustain. He had mana sustain on W(it used to give him mana back), making him best mid laner in game (beside Kassadin who was perma banned). He had better waveclear than Ahri, he had better HP sustain than Ahri, he had mana sustain while Ahri have mana problems. He had combo that could 1 shot any squishy, he had mobility.

It was one of the main reasons why he was pushed into other role, it was officialy confirmed by them. They could take half of the stats, reduce his range and take steroids from him and he could work as non overloaded Burst Mage (which was proposed by his playerbase) but they decided to make him something different because of that very reason. Being fat drunk guy looking for an excuse to brawl is more fitting to bruiser/tank than cowardly ranged nuker.

Balance is not the only thing deciding about a class of a champion. Design, themes and aesthetic decide about it as much.

{quoted}

It doesn't really matter what he was "meant to be". His poke and sustain (and his mobility and disruption) were problematic. Riot reworks him into a tank, and afterwards he's pretty balanced. This same idea can be used to balance other problematic champs, like Ahri.

Ihis poke and sustain werent problematic at all, several months prior to the change poke heal comps were becoming popular in competetive play because it counteracted the "all in" teamfight meta, this was not neccessarily due to poke itself but was primarily due to supports who could long range poke and also heal teams, the main offenders being raka and sona(coincidentally enough this was when support was at its strongest). The supports were nerfed and so were pokes, but gragas was mainly left alone because he was scarcely played and poke was his niche.

The reason they nerfed polke comps was not that they were imbalanced(though supports kinda were), the reason was that it made "pro" games boring to watch which meant less $$ for riot.

Months down the line gragas saw a surge in play because he helped counter the reccuring teamfight meta and he was gutted for it, he wasnt imbalanced, riot just wanted more $$$ from lcs big plays PR.