On second thought, since j7r decides to bring it up after I decided to stop...
To people who love toting the "Pursuit weak" line: name one pursuiter that can switch into any Latios set
"any" is a big word. Any Pokemon can stop Pursuit. Even Cresselia can Reflect/HP Fight Tyranitar and Weavile to death. Tyranitar is a pretty safe bet for the most part, with Specs Draco Meteor not 2HKOing it. Surf can 2HKO TTar, but I'm taking back to the original argument of some people: "it takes no skill to press Draco Meteor". At any chance Tyranitar switches in correctly, Latios will die and Tyranitar will be left crippled. Scizor can handle Latios to an extent too-just stuff EVs into Special Defense and treat Latios like Latias. What I mean is if Scizor has EVs focused more defensively, Latios is essentially Latias to it. You just have to thread carefully like you would with other Choicers. The metagame isn't about countering everything nowadays.
Yes, Blissey does a good job beating the special sets, but that is one pokemon out of almost 480 that are allowed in OU. Latios can obviously "sweep through a significant portion of teams with little to no effort" since the only safe switchin is Blissey
The word sweep is a lot to describe Latios. It's been said that Pursuit threatens it severely, so how does it sweep when it kills a guy and dies to the next? Also, you can switch Bronzong and Empoleon into Draco Meteor if they're EVed correctly. So can Metagross. So can Scizor. So can Jirachi. It's less of centralization and more of adapting to the situation just like you might EV to adapt to something else.
Salamence may be Stealth Rocked, but it still stands that finding a safe switch into Mence is tougher than Latios, because it is more diverse. Switch your Zappy in, get Stealth Rock damage, and die to Specs Draco Meteor or CB Outrage. Celebi swaps in, only to find out Salamence DDed on the switch and is preparing to annihilate it with DDOrb Outrage after Celebi has eaten Stealth Rock (same for Zappy). In another game, a Skarmory tries to switch in, only to be liquefied by Specs Flamethrower. My point is, Salamence gets rid of things quicker than Latios can, even with Stealth Rock weakness, and Latios might let things live in a shot, allowing the opponent to hopefully adapt with his or her remaining check(s).
SpecsLatios falls to suicide baits. If you can keep your suicide lead, for instance alive after setting up a Stealth Rock or whatever, you can switch your dead lead in and nail Latios through Pursuit with your next one. While this same tactic works on any other super hard choicer, Latios is an exception due to its weakness to Pursuit, while everything else can switch out and not die. It's always good to keep a weak Pokemon alive if your opponent lets in a predictable action such as Bullet Punching, and this situation is no exception. You won't have a weak Pokemon all the time, but if you do the results pay off amazingly.
Also we'll all have to be real here. Latios isn't Surfing everytime Tyranitar comes in, or Draco Meteoring every time another Latios is coming in.
Latios' superior speed and typing make it a far better choice for a set like the Memento one. Your question about Uxie is like asking "why isn't Azelf Uber like Deoxys-Speed, it can also use Dual Screen+Taunt+SR!" which is obviously ridiculous.
Deoxys and Azelf are so remotely different in terms of Speed that it's ridiculous. Deoxys hits 504 Speed, Azelf his 361. That's a big difference in comparison to 350 to 317. And again, typing doesn't matter too much because if either can swap in, they can set up Screens and Memento away because they're safer behind the screens. Taunt from anything either prevents the Second screen or Memento, and at least Uxie can U-turn away while Latios has no choice.
...don't encourage me to go further. If you want to debate PM me.