First of all:
SALAMENCE'S DROP IN VIABILITY HAS NOTHING TO DO WITH FAIRY-TYPE POKEMON.
Lots and lots of players seem to think this Pokemon is bad because of Fairies. Have you guys heard of a move called Iron Tail? I'm sure you did. Well, this move allows Mence to LOL at any Fairy-type not named Azumarill. Yes, I know it's inaccurate, but Gunk Shot (with an unimpressive 80% acc) sent Greninja to Ubers. That's because it was able to turn the tables on all the fairy-type Pokemon which could check it prior to ORAS. Focus Blast turned Gengar into a top threat in Gen 4 and 5. Same with Salamence, after a Dragon Dance boost, no fairy bar Azu is safe. Now you could argue that ScarfMoxieMence has taken a hit in viability, but it's not like you could spam Outrage from the get-go in BW anyway, due to Steels being everywhere. So yeah, fairies can annoy Mence a bit, but it's not like it can't adapt. And to be fair, even Azumarill takes huge damage!
You still don't believe me?
+1 252+ Atk Life Orb Salamence Earthquake vs. 88 HP / 4 Def Azumarill: 287-338 (79 - 93.1%) -- 37.5% chance to OHKO after Stealth Rock (Yes.)
+1 252+ Atk Salamence Iron Tail vs. 252 HP / 0 Def Togekiss: 384-454 (102.6 - 121.3%) -- guaranteed OHKO
+1 252+ Atk Life Orb Salamence Iron Tail vs. 252 HP / 252+ Def Clefable: 421-497 (106.8 - 126.1%) -- guaranteed OHKO (unaware still gets 2HKOed)
+1 252+ Atk Salamence Iron Tail vs. 0 HP / 24 Def Mega Gardevoir: 506-596 (182.6 - 215.1%) -- guaranteed OHKO
+1 252+ Atk Salamence Earthquake vs. 0 HP / 0 Def Mega Diancie: 340-402 (141 - 166.8%) -- guaranteed OHKO
252+ Atk Life Orb Salamence Iron Tail vs. 244 HP / 0 Def Sylveon: 455-536 (116 - 136.7%) -- guaranteed OHKO
252+ Atk Life Orb Salamence Earthquake vs. 248 HP / 0 Def Klefki: 348-411 (109.7 - 129.6%) -- guaranteed OHKO
252+ Atk Life Orb Salamence Iron Tail vs. 4 HP / 0 Def Mega Altaria: 294-348 (100.6 - 119.1%) -- guaranteed OHKO