@Riot anybody: What do you want Cho'Gath to be? What is his purpose ingame?
I'm taking a break here from talking about him from a story perspective since it's pretty clear there will be nothing on that front for a long long time.
**But what is Cho'Gath to you in game? What is his ideal state? ** Is he a toplaner? Mid? Jungler? Support? Trollpick ADC?
He's clearly not a close ranged nuker tank, since his synergies with stoneplate have been hit and %HP damage+ True Damage have been made more accessible than ever. A big healthbar bolstered by resists only counters a few of the cast at this point. He gets to win lane against the like.. two non meta toplane champs who he gets to just stat check early, barring excessive jungle presence.
He's not a tank in the traditional sense due to having none of the tools for it. He's huge and just gets knocked around by CC until he falls down unless the enemy team are dumb as heck. He can participate but seldom makes the difference between winning or losing.
Is he meant to scale? Because he starts weaker than the majority of other "scaling" champs and does not ever outscale them. He has many matchups that he simply cannot hope to come back from. You don't get to use Feast to try and scale in a hard lane because it is literally your only threat if somebody tries to towerdive you since his ability to fight is largely gated by whether or not he has his ultimate up.
An AP Juggernaut? Scaling becomes the issue here again, and he's outclassed by every ACTUAL juggernaut in the game at doing that job with the exception of poor, sweet Skarner. He's not scary when he's in the thick of things because his threat range is longer and he usually wants to not be right up close unless he's already just about killed you
Falls about halfway between tank and burst mage: aka too squishy to duke it out but not having enough damage to just remove his enemies from the game without doing so.
An AoE burst mage with instakill potential? This is probably the most rewarding build for him at the moment. Nearly every single high elo Cho'Gath player is building him full AP in order to use his high bases and the increased availability of magic penetration to circumvent his weak earlygame and unreliable scaling. He doesn't need to try and tank with his 0 damage avoidance abilities when he can just remove the source of the damage in the blink of an eye, after all.
I'm not making a judgement call on the mage build. If it's good, and people like it, so be it. But the direction of changes made to Cho and the way he is balanced seems to suggest that Riot wants him to be a big tanky threat yet doesn't know how to do it, or is stuck on the fence about doing that.
I'm under the impression Riot wants him to be bulky and threatening without being overbearing but honestly without the addition of a good AP bruiser item (maybe make it melee only to avoid mages exploiting it) there's little to be done.
Buff his items? Which ones? The AP build will mean buffing EVERY MAGE in the game. The tank build will make tank items better but he doesn't use them nearly as well as the actual tanks do, so for his tank build to become a solid pick past low elo that way it would mean champions like sejuani and maokai become extremely overbearing.
Given the sheer difference in viability between his AP nuker build and all his others, I hope Riot decides if that's what they want for him soon before the playerbase decides for them.
gives good sustain, that builds into ROA which gives good damage and a lot of hp, so your trades are more impactful. AP Cho takes Comet, and maybe ignite to kill his laner, although that means you'll be soaking xp if you want to Feast objectives