I'd like to focus now on Latias. 
		
		
	
	
		 
 
Finally, someone gets off the Latios topic.
 
	
	
		
		
			Her general motive it seems is support/wall. She can become a superb special wall or a pseudo-physical wall if needed.
		
		
	 
 
Can't Bronzong do the same thing, but... not fear Pursuit users and Choice Scarf Heracross?
 
	
	
		
		
			On RL's General/Wish Support sets (special), she can switch into a Modest Scarftran's HP Ice and take 32% tops (Flash Fire Fire Blast does even less!). To pose a semi-immediate threat, they'd have to carry Dragon Pulse (which can hit up to 42%). Latias can then provide excellent Paralysis and other support (depends on the set).
		
		
	 
 
I'm almost positive that this set would attract Electivire... a lot. Especially since its Expert Belt'd Ice Punches can actually muster up some damage to Latias. I'm also sure that this would just encourage faster Pokemon to use Taunt, like, Alakazam, Weavile and Azelf who all don't mind her Dragon Pulses or... Draco Meteors?
 
	
	
		
		
			Ground types that switch into the T-Wave can't do much back, as their STAB misses without Gravity and lack anything that can hit back hard (Maybe Flygon, but come on; if I'm forgetting something else, let me know).
		
		
	 
 
Swampert can bust it up with Avalanche if Latios doesn't carry Grass Knot. If does carry Grass Knot, Blissey can just stop it with a hopeful Toxic.
 
	
	
		
		
			Latias is good for those that acknowledge the need for a special wall, but despise Blissey for whatever reason. It should be mentioned that SE hits still hurt pretty bad (Modest Max 'Mence Draco Meteor can hit 74% minimum) and that physical blows rip her apart.
		
		
	 
 
You forget that most Mence run Outrage with either a Life Orb, a mixed set, a Dragon Dance-Lum/Yache Berry set or just Choice Banded. I highly doubt that Latias will like taking hits like that. I really haven't seen a full SpecsMence in so long...
 
	
	
		
		
			And when a huge threat comes in (cough T-Tar cough), Pursuit is always there ready for her >.> (won't KO, but it'll hurt like a @#$%&).
		
		
	 
 
Tyranitar, Weavile running Taunt, Heracross *Scarfed* (or, Banded if Latias only has Dragon Pulse), anything running a Physical SE move with either Speed or Bulk can mess with her.
 
	
	
		
		
			For the Physical Support, she can't take blows very well at all (so I recommend against it), but if you need a Breloom SubPunch counter, she's probably the best you can get with Psychic stab (if you have it, Dragon pulse is still a 2HKO, or OHKO with Sub+SR). Again, I recommend against this because any SE hit will rip her apart and any non-SE will still hurt pretty bad.
		
		
	 
 
That's right, hopefully, RestTalk would be an option as a counter for Breloom, assuming that Spore already hit a Pokemon on Latias's team.
 
	
	
		
		
			Dual Screen, gotta love this. This set has potential to provide great team support (much like speed Deoxys) and allow safe setup while your team takes reduced damage all around. A lot of potential here, but I feel it may be overlooked/shadowed by the other sets (namely the supports).
		
		
	 
 
So many things can run this either with more bulky or, Speed. Again, this'll just encourage faster Taunt users to come in on Latias. In fact, Trick users can snatch its Light Clay away and make it only able to setup a single Screen.
 
	
	
		
		
			While her SpA isn't as good as her other half, it's still up there. Base 110 isn't something to mock. Alongside Calm Mind and Attacks with good coverage (see Latios), Latias can potential sweep anything that comes her way as she can take priority blows a bit better. Timid would probably be the best option here to outrun any immediate threat while CM will boost your SpA. I'm definitely going to devise a set to take advantage of this (walling was never really my thing) and I'll get the set up once I think it over and make it "flawless."
		
		
	 
 
This will only get things that can sponge Special hits better (namely Blissey, Steel Types and Zapdos) to increase in popularity. Roar/Whirlwind users can rejoice (yay, CMShuffle Suicune!) as Latias can't do much to them.