Landorus isn't broken either, it is hard to wall, but you can revenge kill it as easy as fuck. Ex: Greninja Ice Beam = done, really easy.
Oh boy, this argument again. Here, let me continue that for you:
Mega Kangaskhan isn't broken either, it is hard to wall, but you can revenge kill it easy as fuck. Ex: Terrakion Close Combat = done, really easy
Mega Lucario isn't broken either, it is hard to wall, but you can revenge kill it easy as fuck. Ex: Scarf Landorus T = done, really easy
Genesect isn't broken either, it is hard to wall, but you can revenge kill it easy as fuck. Ex: anything with a frigging fire type move = done, really easy
also, did you ignore where I said Lando can run a Rock Polish set, easy wiping out all those "checks"? have fun sending in Greninja when you get OHKOd by Focus Blast or Earthquake.
What I'm trying to say here is that simply saying checks exist has never been an effective argument when deciding whether or not certain Pokemon are worthy of a ban. It's important to consider how easily those checks can switch into Landorus, how easily Landorus can come into other Pokemon, and how easily Landorus can force other Pokemon out. Landorus in particular has plenty of opportunities to switch in thanks to excellent immunities to ground/electric type moves and resistance to Fighting. It also can reliably win 1v1 against the vast majority of Pokemon in the tier with less than 101 speed. Just from the A/S ranks alone, we get:
Aegislash, Mega Charizard X, Azumarill, Bisharp, Clefable, Excadrill, Gyarados Mega, Mega Scizor, Tyranitar, Venusaur, Mega Charizard Y, Ferrothorn, Heatran, Hippowdon, Kyurem B, Landorus T, Mandibuzz, Breloom, Chansey, Diggersby, and Skarmory
It's a safe bet that you're going to see at least ONE of these Pokemon at least once every other match (probably more so), so using Landorus to force something out is extremely easy to do. And no other Pokemon can wreck predicted switchins as easily and reliably as Landorus- if the Lando user knows what faster check you're going to switch in, it can almost always OHKO it. Not even Kyurem B can do that.
It's this sort of "play by gut instinct" mentality that's become all too common in the OU tier right now. If the ONLY way to handle a Pokemon is to either sacrifice something or bank on gut instinct (which in practice is little better than luck) to switch around it, then it inherently removes strategy and higher level thinking present in a meta. It should take some actual EFFORT to sweep with something like Lando- if it required several layers of hazards and certain common checks to be completely removed before it could start OHKOing things left and right, I could understand it being balanced, but as it stands it requires zero team support or strategic thinking to use properly and is forcing people to run way more flimsy attackers with Ice type moves than they surely would have otherwise.