But then again how rare would it be that someone would just happen to have perfectly IV and EV'd a Salamence with a beneficial nature? And then to have taught it Outrage? I just don't see this situation as being fairly common.
Sure people IV and EV train, but I doubt that a perfectly IV and EV'd Salamence has been done yet.
In really competitive battling and Shoddy environment, every Salamence has perfectly IV'd Pokemon with the optimal EV spread. In addition, the perfect IV in this situation ONLY refers to Salamence's IV (which would be 31 in this case), which is quite easy to attain, compared to full 31's. I have quite a few Pokemon with 31 in one or two stats myself and I don't breed nearly as much as the people who actually care. The nature is easily fixed by giving the parent with the appropriate nature an Everstone; there will be a 50% chance afterward to pass on the nature.
Outrage is also one of Salamence's attacks-of-choice, giving it STAB, great coverage, and immense power.
On the other hand, you also shouldn't criticize the Salamence for being perfect because I also assumed the Dragonite would be optimized as well. I gave it a neutral nature in DEF because most Dragonite builds indeed DO have a neutral nature for DEF (otherwise, it is actually DEF-hindering, like with Mild). I also maxed out Dragonite's DEF and HP EVs, which no one in the right mind would do.
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edit Also, using MetalKid's calculator;
https://www.metalkid.info/pokemon/OnlineProgram/Calculators/DamageDP.aspx
I received results --
Defender HP: 323
Damage: 387 - 456
Damage: 119.81% - 141.18%
Of course, Dragonite DOES have Ice Beam, but SPD is a huge factor in this draw, and ultimately, the final call to see who wins. If Dragonite does move first because of some awkward reason, of course Salamence would fall.
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edit2 If anyone was wondering, here are numbers for Dragonite > Salamence:
Ice Beam --
Defender HP: 331
Damage: 365 - 430
Damage: 110.27% - 129.91%
Blizzard --
Defender HP: 331
Damage: 460 - 541
Damage: 138.97% - 163.44%
Draco Meteor --
Defender HP: 331
Damage: 401 - 472
Damage: 121.15% - 142.60%
Outrage --
Defender HP: 331
Damage: 443 - 521
Damage: 133.84% - 157.40%
I only picked moves that were Super Effective and commonly used on Dragonite, along with Blizzard, since it was mentioned.