Guys, guys. What do you mean, Darmanitan doesn't deserve an analysis? Sure, it's walled by physically bulky Water-types; big deal.
There are plenty of Pokemon that rely on recoil-based moves, such as other physical Fire-types, Deoxys-S, Talonflame, Staraptor, and physical Thundurus, and many of them are weak to Stealth Rock. Also, about 35 out of the current 139 Pokemon getting an XY OU analysis are weak to Stealth Rock. That's right, 25%. With the prevalence of Defog users, who are now very common on standard OU teams, being weak to Stealth Rock is clearly not a big deal judging from the sheer amount of Pokemon weak to Stealth Rock in the meta.
I agree with BurningMan about the Scarf set being outclassed by other Scarfers. Personally, I never really liked the Scarf set at all, for the reasons BurningMan mentioned. But the All-Out Attacker is perfectly viable, I don't understand why people are bashing it. Sure, it's walled by physically defensive Water-types; every Pokemon has their shortcomings, and there's something called 5 extra teamslots to take care of Pokemon such as Quagsire or Slowbro.
Let's see how Darmanitan matches up against the metagame.
S Rank
Aegislash
OHKOes every time, no matter the variant. Can take a hit or two as well. WIN
Mega Charizard X
OHKOes with EQ with Adamant + Life Orb. 75% chance to OHKO Bulky WoW set with Adamant CB EQ, guaranteed after Stealth Rock damage. OHKOes upon switch-in, otherwise is outsped and OHKOed. KIND OF A WIN
Deoxys-D
252+ Atk Choice Band Sheer Force Darmanitan Flare Blitz vs. 252 HP / 244+ Def Deoxys-D: 229-270 (75.3 - 88.8%) -- guaranteed 2HKO
252+ Atk Choice Band Sheer Force Darmanitan Flare Blitz vs. 252 HP / 4 Def Deoxys-D: 294-346 (96.7 - 113.8%) -- 81.3% chance to OHKO
That's ridiculous!! And it can't do a damn thing in return. WIN
Deoxys-S
Darm easily OHKOes on the switch, AND ACTUALLY LIVES A PSYCHO BOOST FROM DEOXYS-S. It will die from recoil damage, though. WIN (SOMEWHAT)
Landorus-I / Thundurus-I (grouping them together so as not to say the same thing twice)
OHKOes on the switch, but is outsped and OHKOed otherwise.
A+ Rank
Azumarill
252+ Atk Choice Band Sheer Force Darmanitan Flare Blitz vs. 252 HP / 0 Def Azumarill: 267-314 (66 - 77.7%) -- guaranteed OHKO after Stealth Rock and 3 layers of Spikes
Does a ton of damage to Azumarill and can then switch into a check or counter such as Venusaur. KIND OF A WIN HERE
Bisharp
Barely lives Sucker Punch and OHKOes. WIN (SOMEWHAT)
Charizard Y
Darm lives a hit with a good amount of health and OHKOes. Can also take advantage of Charizard Y's Drought ability after taking it out. WIN
Garchomp
2HKOes by using U-Turn earlier in the match (and providing useful switch advantage) and finishing it off later in the match with Flare Blitz. Otherwise outsped and OHKOed. KIND OF A WIN
Greninja
Flare Blitz and U-Turn OHKO!! Otherwise outsped and OHKOed. KIND OF A WIN HERE
Gyarados (Mega)
Darm outspeeds and OHKOes. WIN
Keldeo
Darm does a ton of damage with Flare Blitz and can then switch to a counter, but Keldeo outspeeds and OHKOes IN THE MIDDLE
Mega Mawile
Darm lives a Sucker Punch and OHKOes. WIN
Mega Pinsir
Pinsir can't switch in on Darm for fear of being OHKOed, but outspeeds and OHKOes Darm. IN THE MIDDLE
Mega Scizor
Switches in freely and OHKOes. EASY WIN
(WIP will add more later)
A Rank
A- Rank
As you can see, almost nothing can switch into Darm, making it a ridiculously good wallbreaker if it gets a free switch-in.