the fact that some people think that it is totally reasonable to handle lando by having a check as well as perfect prediction when lando comes in so your check doesn't get screwed over on the switch just screams that something is wrong to me.
Take what you just said, and reverse it.
Say you make a team and all you have is a check to, say, Scarf Keldeo (fuck what anyone thinks, Scarf Keldeo is not inherently broken). Now when playing Scarf Keldeo with only one check (let's say here, I don't know, offensive LO Celebi. Bear with me for a moment).
252 SpA Keldeo Hidden Power Ice vs. 56 HP / 0 SpD Celebi: 152-180 (42.81 - 50.7%) -- 96.09% chance to 2HKO after Stealth Rock
So if you switch in on the HP Ice with rocks down, you're fucked either way tbh.
But Scarf Keldeo users know that, generally speaking, it's rare to use HP Ice seeing as how it has rather limited use compared to its other moves. Celebi isn't 2HKOd by anything else Keldeo has, rain boosted Hydro Pumps aside.
Your opponent knows that your only real answer to Keldeo is your Celebi. So what does your opponent focus on? Fucking up Celebi, of course.
Back to the Landorus argument - I'm not saying throw a Scizor on your team and you'll have no Lando troubles, that's a shit argument. What I AM saying is that your check is just that - a check. If Keldeo HP Ices later, maybe you can bring in your Volcarona and QD, meaning that Celebi is a successful check because your opponent rarely ever wants to use that HP Ice on Keldeo (against any team, not just theorymon).
Now look at this in regards to Landorus:
You have something which, despite good bulk and defensive typing, is difficult to switch in directly. You physically cannot do all that you want to with 4 moveslots - and most sweepers are, to a certain extent, able to (Garchomp, Breloom, CM Keldeo, etc.)
On top of that, even though you're not choiced, you have to predict very well. Don't give me shit about "I predict well" or "in the hands of a skilled player" because it's not about all of that, it comes down to damn luck whether or not your Landorus dies because you used Rock Polish instead of just killing that Tentacruel with Earth Power.
It's not "perfect prediction". There is no such thing and it's utter bullshit how much that gets brought up in theorymon. Any high-powered OU sweeper is broken with "perfect prediction". Lando requires less than normal since it doesn't need to go choiced, but it's still not broken.
Additionally, making one prediction that can do just that much more damage to Lando that puts it closer to BP range, or that can screw over the opponent's team is a part of Pokemon. Do I lead with Terrakion because I think he'll lead with Ttar, or do I lead Heatran because he might also lead with Forry? Terrakion vs. Forry is an easy kill for Forry with Gyro, Ttar vs. Tran usually favours Ttar. Granted, these choices aren't normally as massive as "do I switch anticipating the Earth Power or stay in on the now over-predicted Rock Polish?" but they are EVERYWHERE.
tl;dr Lando isn't broken