To begin again, Swarm Durant? Why would you ever choose to run a swarm Durant. Hustles accuracy drop yes can be quite the flaw, but hustle will always trump swarm. Hustle is the basis of Durant's massive power. Without it, while still being viable, is B Rank. Swarm should almost never be used on Durant. 80% is admittedly not the greatest odds, but if that's the reason you would be losing, run a separate revenge killer. Plus, Some other revenge killers moves, like focus blast, have only 70% accuracy. 70% is even worse than 80% and Sceptile and Accelgor run it all the time. In order to use Durant effectively, take time to analyze his 4 sets and decide which one is the best for you
While Durant honestly doesn't have ghost fighting coverage, That doesn't mean its hits hit everything not very effectively. IMO, I've played with Durant a lot and Steelix
does not counter Durant. Every good Durant set runs superpower, which, even only at plus one, sends the massively bulky Steelix to the hills. Plus, with Durant's
112 base defense Steelix isn't going to be taking it out. 252Atk Life Orb +1 Hustle Durant (+Atk) Superpower vs 252HP/252Def Steelix (+Def): 90% - 106% (322 - 378 HP). Guaranteed 2HKO. 42% chance to OHKO. This is full bulky Steelix having a 42% chance to be
OHKO'd by only a plus one Durant. As for Poliwrath and Qwilfish, you make a valid point. However, 252Atk Life Orb +1 Hustle Durant (Neutral) Superpower vs 160HP/0Def Water Absorb Poliwrath (Neutral): 97% - 114% (352 - 414 HP). Guaranteed 2HKO. 85% chance to OHKO, This is Durant at only a plus one against a SubPunch Poliwrath. Qwilfish reliably counters Durant, but every Pokemon has counters, regardless of how good they are.
Every relevant calculation? Life Orb is often a necessity and hustle already makes him powerful, but every relevant calculation. That is simply false. X-Scissor already packs an INCREDIBLE wallop with only hustle and LO, and to be clear, when I said wide lens was a possibility, I didn't mean wide lens was even close to being his best option. Life Orb does give him the extra punch he needs. However, If you have a solid enough RU team and the primary reason you fail is not power, but accuracy. It is a possibility that you might want to run a wide lens. Yes, LO is almost always a better choice, but the Smogon article here
http://www.smogon.com/dp/items/wide_lens says that if accuracy is your greatest downfall, consider a Wide Lens.
Your first statement is spot on, his power and speed are impeccable. But if played right, there is a 95% chance for Durant to hit something hard. Unless the team is Qwilfish, Poliwrath, Steelix maybe, Sceptile who is already unburdened, Accelgor, and maybe a Cryogonal as a revenge killer, Durant is going to hit something, and probably kill it. I didn't say he was unbeatable, I said he was good. Definitely good enough for low S rank. So,
Durant for S Rank. He is a good, fast, strong, well typed Pokemon who is incredible in the RU Pokemon.