I disagree that Salamence should be Uber, since I feel that there's always going to be one sweeper that exceeds in skill above others. While I have limited experience playing Pokemon, from all my battles with Salamence variants, I usually found them to be easily counterable when a little bit of thought is used. I think a lot of competitive battlers have gotten into the habit of thinking that just because something doesn't have an extremely obvious counter (say how Gliscor counters Heracross), it is broken and ought to be banned. While it is true that there are probably no direct counters to all of the variant Salamence sets, it doesn't necessarily mean it's broken. Salamence is just an extremely good Pokemon.
The point isn't that Salamence is the best and thus too good, or hard to counter and thus too good.
Lucario is similarly "hard to counter" since it can carry one move for each of its possible hard counters (that is to say, it can carry Crunch for Rotom, Stone Edge for Gyarados, and Ice Punch for Gliscor) with Gliscor the only remaining pokemon with any semblance of an ability to "hard counter" Lucario since an Ice Punch + Extremespeed might not KO and definitely won't without Stealth Rock... but nobody's arguing that Lucario should be a suspect at all, because it's predictable and limited enough by its moveslots to keep it perfectly reasonable.
The problem with Salamence is that even with pokemon that are set up to blockade it, whatever Salamence comes in on, if you aren't already carrying priority or a fast hard attack (in which case the Salamence player screwed up anyway), you're going to HAVE to switch and whatever you switch to is guaranteed to lose far too much health. You can't switch in anything safely at all since there's such an incredibly limited array of pokemon that can survive
any attack from Salamence, let alone if they predict correctly and nail you with a super effective attack. Sure you brought in your physically bulky Porygon2 and Traced Intimidate, but you just got hit by a Fire Blast or Draco Meteor. Specially Bulky Porygon2 instead? Well you just ate an EQ or Outrage. Porygon2 is the single best-equipped pokemon for switching in on Salamence, and even then there's a good chance Sally will still crush the poor duck instantly because of P2's disappointing lack of
resistances.
And that's even before bringing up that P2 can't do anything back to Salamence once it's in. If Sally Danced, even a Scarf can't make P2 outspeed it, and if it didn't dance, P2 got hit for at least 50% of its health and will die next turn before making a move.
Basically, the argument against Salamence is much the same as the problem with Garchomp - that it can too easily tear down at least one pokemon per battle, and there's really not a whole lot you can do about it unless you, effectively, get lucky and out-guess your opponent. Salamence doesn't have Garchomp's bulk or Swords Dance, but it uses Life Orb instead, a different set of resistances (including Ground immunity), is faster after a Dragon Dance, and trades the raw power on the physical spectrum for an extremely capable Mixed variety that makes it even
harder to come in on. Not only that but even with Mence's lower attack, Life Orb + Dragon Dance is VERY close in power to Chomp's SD. the only thing Mence is really missing is STAB on Earthquake.
Salamence is not uber, period. True, it has some extremely good stats. Speed, Attack, Special Attack, reasonable defenses backed by intimidate. It's versatile because it can run so many sets, including mixed, dd, specs, etc. However, Salamence does not fill the role of other fellow ubers. The metagame does not centralize around him. It's not really that hard to take Salamence down. And don't give me bullshit about counters either. Pokemon is more than just countering. Latias can beat it 1 on 1, and Scizor can revenge kill it. Swampert, Vaporeon, and Suicune can all survive +1 outrage and KO back with ice beam. This being said, I honestly don't think Salamence should go to ubers.
I'd also like to point out that there is no "centralization characteristic". If there was, Scizor would be Uber in a heartbeat right now. Centralization tends to be an end result of a Pokemon being overpowered, but it isn't a requirement and isn't an absolute. Wobbuffett is currently the only pokemon banned despite not technically meeting any characteristics, and it didn't even centralize the game - it just absolutely sucks ass to play with and against it, not to mention the fact that Shadow Tag outright breaks the game state (hence Wynaut's banning alongside Wobbs despite its significantly lower stats).
Latias can beat Mence 1 on 1... unless Mence Danced, in which case Latias is SOL and JWF. Unless Latias is Scarfed, which is pretty insane in and of itself (Choice Scarf on a base 110 speed? it takes pokemon the likes of Skymin, Garchomp, Latios, Salamence, and Deoxys-S to cause that one... and we all saw the results of the first part of stage 3... that was one goofy metagame). Not to mention if Latias comes in on a Meteor or Outrage, she's flat out dead or at least crippled beyond repair.
The bulky Waters can do the job, but they can't switch into Garc--- Salamence, and they're all too slow, relegating every one of them to "Revenge Killer".
I think that's actually a pretty good measuring stick right now, actually, for the Offensive Characteristic. When the
best solution is to let something die so you can revenge kill, the pokemon is too strong. The only other pokemon right now I can think of that's like this more often than not is Latias. Nothing else really meets that condition.
edit, addendum:
You also consider all the priority moves there are in today's metagame. That's a big part of the reason why "Bulky Offense" is a large part of the OU metagame. Scizor and Metagross can hit him with Bullet Punch, Lucario has ExtremeSpeed, among others.
Look at what you just said though. You were saying this in response to "Switch in counter, but watch a Dragon Dance." None of those priority users can switch into Salamence with any remote semblance of safety. If it's a MixMence and it uses Fire Blast on the Switch, all three of those pokemon are absolutely cooked. Earthquake hits all but Scizor extremely hard, as well.
And then there's Draco Meteor - against max HP Scizor, the "New MixMence" build does about 50% of Scizor's health on the switch in, and Scizor has only a ~50% chance of KOing it back with Bullet Punch (though if it fails to KO, Mence still dies to LO recoil on the next attack).
Metagross may be a strong priority user, but even a CB 252-attack Adamant Metagross does all of
607 Atk vs 196 Def & 331 HP (40 Base Power): 135 - 159 (40.79% - 48.04%)
with Bullet Punch to a 0/0 Salamence. If Mence has only taken SR damage, Metagross is
dead and there went your "counter" to Mence.
Scizor fares much better - again, CB 252-attack Adamant
591 Atk vs 196 Def & 331 HP (60 Base Power): 195 - 229 (58.91% - 69.18%)
which means Scizor is dead if Mence has only taken SR damage, and a low enough damage roll (65% or less, which has about a ~60% chance of occurring) means Mence won't die to Life Orb recoil, leaving Mence one more turn to smash something before dying. Unless your team is carrying a second priority user... and God forbid you don't have SR up because if it's not, Mence can repeat this process even with another priority user on your team.
This also disregards the clear issue of your opponent pulling Mence out of the fray temporarily to bring in Magnezone on your Choice Band-locked Bullet Punch and laughing its way to the bank. So much for your Sally checks.
Also, Ice Shard users have it even worse. The only move any of those can come in on is Earthquake (Mamoswine and Donphan), anything else is pretty much dead on the switch in.