I know I'm gonna get downvoted because everyone hates him and all that but screw it I'm gonna speak my opinion anyway.
When patch 9.9 came out it was a great patch because it made two unplayable champions playable again (Tahm and Aatrox). Yes I know many people will complain that it brought more cancerous champions to top lane but I think whoever made those changes did a good job.
When you make a bunch of changes like those to Aatrox and Tahm you can expect them to be either way too op or too weak. Whenever a champion gets reworked or is released into the public for the first time they are always either too strong or weak and that’s because it’s hard to get a champion made correctly first try. There’s not a good way to know how the champion will be until you see how players interact with each other regarding those changes.
So yes they both became op which is not a surprise but that doesn't mean the balance team should just immediately give up and just gut Tahm again. It makes no sense, why are they putting effort into Aatrox to get him into a spot he deserves but Tahm can't get the same love? If you are gonna make a bunch of changes to someone like with Tahm and Aatrox, you might have to go through trial and error to fix the problematic parts of the champion.
All they needed to do was nerf his passive damage and make it scale again like it used to and increase Q cooldown. Heck they could have even given his Q a unique champion cooldown like Yasuo's E or Rek Sai's W. Something like: If champion has been stunned by Tahm's Q, then they can't be stunned again for X seconds.
But nope rather than trying to help some gutted champions get back in a good spot you just instantly give up after only 2 attempts of patching him.