First don't mess up between counter and Revenge kill, it's absolutely not the same thing, every pokemon can be revenge killed.
		
		
	 
I'd like to see you revenge kill something like Arceus above ~30% HP.
	
		
	
	
		
		
			If you start by saying that you have to rely on prediction to see his set, why did we ban deoxys then ? With a bit of prediction, you could check his set and counter him well. No it was ban cuz it didn't have any sure counter like landorus doesn't have any also.
		
		
	 
Because even WITH prediction you can't stop Deoxys-S. Nomatter what you do, it IS getting a screen up, probobly both, if you lead with something without Taunt. Deo-S is also virtually guarenteed hazards, and preventing you setting them up
 is guarenteed. LO cleaners were also pretty tricky to stop, due to outspeeding everything.
Same with most Ubers, they're uber because even WITH prediction you can't stop them, or they require stupid amounts of it/punish mispredictions FAR too hard. It dosen't matter if you predict an Exacadrill earthquake, switching in Skarmory isn't going to stop it, at best you'll WW it out after taking a Rock Slide, at worst you'll get flinched and be crippled enough that you'll be KO'ed next time you come in... especially if you bring in something you can't Roost on.
	
		
	
	
		
		
			To be counters , a pokemon needs to avoid a 2HKO when switching on it which isn't the case for skarmory and latias which are both 2HKO, depending on the version.
		
		
	 
It dosen't change the fact that the SET has counters. Also, Azumarill can switch in on pretty much anything Landous does [Especially as Landorus has to setup to be much of a danger], withstand it, and OHKO with Aqua Jet. Azumarill is actually a counter.
	
		
	
	
		
		
			Prediction isn't an excuse to counter a poke, cuz its same as for revenge killing, every poke can be countered with a bit of prediction, either thundurus or garchomp. No to be Uber, a pokemon must have any 100% sure counter which is the case of landorus.
		
		
	 
Explained above. Also, stop using the Gen 4 defnition of an Uber. You can't counter 300+ pokemon, and even more sets, with a team of 6, checks are now what we rely upon.
	
		
	
	
		
		
			I'm speaking in theory. Any OU what ever the set  they are running are supposed to have at least one sure counter.
		
		
	 
This isn't true now, and wasn't true in Gen 4 either. 
- Infernape. Especially when Latias was banned. Starmie comes close, but what about Grass Knot, or even some crazy SD Thunderpunch?
- Lucario can hit practically everything SE, hard.
- Starmie, few things can weather it's attacks, and Trick kills Blissey/Chansey
- Gengar has so many sets...
- In Gen 5, Dragonite [Volcarona and Terrakion are both absolutly stopped by status. And Scizor can switch in on Terrakion as it sets up. And Azumarill can switch in and OHKO Volc]
- Voltturn has no hard counter