Latios will not be moved down to OU. Latias was moved down due to the way the metagame works now. It's all about hitting hard and fast and the use of walls have greatly diminished. Latios remains a very potent sweeper in the Uber environment from what I can tell, whereas Latias doesn't have the sheer stats to really compete. Correct me if I'm wrong, I very rarely Uber.
No offense but that's wrong. Latias in Ubers was more popular then Latias or so Smogon says. Latias can function as a tank but in Ubers it took its far better then Latios and could KO something. Most importantly it can actually take a hit or two. According to statistics Latias is used more then double Latios and
even Tyranitar and Scizor is used more then Latios. 194 Defense can't cope with the Uber metagame so it will be downgraded.
130 SpAtk is fearsome but it's easily revenge killed. Weavile or Dugtrio can used Pursuit/Sucker Punch repesctively to land a huge hit on him. Even when he's full health Pokemon with Sucker Punch can land a huge hit on him. 305 HP /194 Def is even less bulky then Salamence who has Intimidate to cope with his wose Def and higher HP.
Here's some damage calcs for Latios with 0HP/0 Def/0 SpD
Jolly 252 Atk CB Dugtrio w/ Sucker Punch -
76.41% - 89.70%(Sometimes OHKO w/Stealth Rock)
Adamant 252 Atk LO Toxicroak w/ Sucker Punch -
87.71% - 102.99%(OHKO with Stealth Rock 100%)
Jolly CB 252 Atk Weavile w/ Night Slash -
130.90% - 154.15%(OHKO no matter what)
Timid CS 252 SpAtk Jolteon w/ HP Ice -
56.48% - 66.45%(2HKO no matter what)
Now some for Latias with 0HP/0 Def/0SpD
Jolly 252 Atk CB Dugtrio w/ Sucker Punch -
69.44% - 81.73%(Never OHKO even w/ Stealth Rock)
Adamant 252 Atk LO Toxicroak w/ Sucker Punch -
79.73% - 93.69%(W/ Stealth Rock never OHKO'ed w/ Stealth Rock OHKO is possible)
Timid 252 SpAtk CS Jolteon w/ HP Ice -
48.84% - 57.48%(Sometimes 3HKO or 2HKO)
Latias's extra bulk helps. She can survive Dugtrio and OHKO back with Ice Beam and since these EV spreads are for Choice Specs Latias can easily OHKO Toxicroak and Jolteon will fall to Choice Specs Dragon Pulse in 1-2 hits. Look none of these Pokemon are counter so don't bite my head off but seriously Latios isn't that scary. These Pokemon make good revenge killers against Latios and he can't really beat them as usually he will be damaged when they come in.
And sheer stats? No offense what are Latios's sheer stats? Base 110 Spe? Well Latias has that too. Base 80 Defense? Don't make me laugh. Base 90 Atk? Pah Salamence runs a DD set much better. Base 110 Sp Def? Pretty good but he never invests in it so it sits at a meh 255 SpDef which is pretty nice but not
sheer. Base 130 SpAtk is his only sheer stat which is great, no one can deny that.
I'm not saying Latias is better or Latios is better. They are both great Pokemon but I think some people are overestimating Latios. I've faced a few, he wrecks havoc with Draco Meteor but he is beatable and personally I like Latias better.
Why? Maybe I'm crazy but 110SpAtk is good enough for me and I like the fact even without EV's she still has 216 Def/295 SpD which is pretty bulky.