How is Dragonite's Dragon Dance set outclassed by any of those? Latis attack specially and Garchomp Swords Dances while Dragonite can raise insane speed+attack at the same time while being a pain to kill with Multi-Scale, superior defenses and Roost. The only pain is whether to go with Fire Punch or Earthquake (Fire Punch hits Nattorei, Skarm, and Brongzong which Earthquake can't/can't hit well although there was one battle where I ran into Tormentran and was stalled out and lost because I couldn't hit the dang thing very well which made me really wish for Earthquake). Dragonite is bulky as heck and while Salamence can be, he can never hope to be quite as bulky as Dragonite (without Intimidate against the first pokemon) in the same way. Even Dragonite's offensive Dragon Dance set is phenomenal since it is still one of the best Dragon Dancers, period.I'll do one better, Accidental. Here's a link to a warstory where one of the (very good) battlers makes excellent use of a Defensive Mence, and proves why Intimidate is probably the deciding factor in it's use whilst doing so: Linky
I'd also like to add that at present, with Lati@s, Chomp, and such still in OU, Mence's offensive sets are somewhat outclassed, as are Nite's. This battle I believe justifies the greatness of a defensive set on him, which is a useful new niche.
But Salamence is quite an able physical defender with Intimidate and invested defenses. I don't know if he should be running Dragon Tail though. But it is effective.