I agree with you on everything except the cho. Cho dies faster than other tanks despite his hp stacking ult because his scaling with defensive items isn't as good as most other true tanks. Maokai, poppy, malphite, nautilus, sion - they all have kits that enhance the defensive items they buy while cho only has ult stacks to do so. Because hp stacking is so punished by champs and items (so many %hp damage on items), cho is super squishy compared to what one of said other tanks are with the same hp and defensive items.
Also, Cho's damage only scales to be a true kill/1-shot threat IF he can get several (around 3+) ult stacks beyond his 6 "free" ones. His lane sustain is not as good as other champs because it requires he kill off minion waves - if he can be zoned, he can easily be whittled down - unlike maokai. He's highly vulnerable to ganks; however you can totally 1v1 him early and use that to build a lead and continue 1v1'ing him mid/late if you play properly. You can't do that if you braindead sit in the minion wave farming and never punishing him. You need to stand out of the wave - forcing him to attack YOU OR MINIONS - never both at the same time. Zone him off cs or force him to blow spells just to farm. Freeze him out of lane. It's no different from how you are supposed to play against gp. Cho is good sure, but he's not broken.
He must actually put in a lot of work to get to 1-shot potential. Surviving an early laning phase where he can generally lose the 1v1 and is easily punished via ganks since cho naturally pushes when he farms while having no escape mobility tools. Engaging teamfights where he has less reliable engage than tanks with gapclosers. Being denied ult stacks via teammates ks'ing last second or enemies getting a last second spammable shield/heal in to deny him a stack. Potentially blowing flash - his only safety net - to get a stack. He has to take more risks than other tanks to do his job. He's not as tanky as them unless he's got 2x his normal stacks for any given point in the game. And his reward for all this is... he actually deals meaningful damage. If you let a tank get so many stacks that cho is "broken" in that game; you would have lost regardless of what toplaner was being played. Because if you can't deal with the squishiest 0 mobility tank and his team, then you wouldn't be able to deal with some other tankier champ who offers more reliable engage and equally solid base damage.