I support S- and S+ ranks now. I know that idea was shot down in the XY ranking threads, but back then, it was just to show the tiniest differences in viability of the S ranks. Now, there's a pretty clear difference because some of the S ranks are really really good (Latios, Charizard X) and some (Salamence, Greninja) are straight up overpowered.
Speaking of Greninja and Salamence, it's no small feat to check/counter both of them with the same pokemon. So I support raises to Mega Aerodactyl, Weavile, and Porygon2. Of course Salamence and Greninja aren't the only newcomers they beat:
Mega Aerodactyl is faster than every new mega, with a Jolly nature. So it can at least get a hit off vs anything. Not only that, but it can check/counter them, because it can both switch in and OHKO back. It straight up counters Mega Beedrill, can switch into Camerupt's stabs and OHKO with Aqua Tail or hurt it bad with Earthquake, can switch into any attack from Sceptile once and OHKO with Wing Attack or Ice Fang, can take a kick from Mega Lopunny and OHKO.
Weavile got Icicle Crash, which is a ~13% power increase over Ice Punch. Since that's its strongest move after Knocking Off an item (or if Knock Off is resisted), that's pretty significant. For example, it can beat CM Mega Latias more quickly. And it's basically the only physical attack that bulky Mega Salamence can't ever set up on. Wait, did I say "ever"?
-1 252 Atk Life Orb Weavile Icicle Crash vs. 252 HP / 252+ Def Salamence: 380-452 (96.4 - 114.7%) -- 81.3% chance to OHKO (you may recognize that as a 18.7% chance to NOT ohko)
Fuck Salamence, guys.
Finally Porygon2. Less overly powerful wall breakers like Heracross is always welcome, so Porygon2 can stand up to a lot of the new megas just by being bulky as hell and having only one weakness. Specifically, it takes on Altaria, Beedrill, Glalie (and survive its explosion), Latios, Metagross, Pidgeot, Sceptile if it doesn't switch in on Focus Blast, Salamence, Sharpedo, Steelix and Swampert even in their respective weathers. I'll just link the post I made in another thread:
http://www.smogon.com/forums/thread...ns-nor-aegislash.3519695/page-82#post-5823902
Another small perk is reverse trapping Magnezone and Dugtrio using Trace.
I haven't played that much ORAS OU yet, although Suicune could be lowered a few ranks because it now has to compete with mega Slowbro for a bulky Water-type, as Mega Slowbro has a lovely Fighting resist and infinitely more physical bulk. Mega Slowbro also has more initial power than Suicune does, so I think Cune should drop some sadly. Mega Slowbro also is superior to Suicune in the sense that it can never get critted so it's as a result much harder to stop.
No
Suicune is actually the one with the better typing. The CM sets aim to wall everything, and less weaknesses is better. Having a Fighting resist isn't very useful for a CM sweeper, while it gives Slowbro something to switch in on, once it's actually trying to sweep, the opponent will just not use fighting moves against it, and can instead exploit its 3 extra weaknesses.
Suicune is also faster, which is a little more useful than it seems. Against those slower opponents, it allows Suicune to KO or burn opponents with Scald a turn earlier, Suicune doesn't have to anticipate the turn before when it's low on health to recover health, and it can Calm Mind first to reduce damage against stuff like Mega Venusaur.
Finally Suicune is just as viable as ever if you were using a different mega.