I think I'll propose something rather radical. Shoot me down if you want, but I firmly believe this change could happen.
Bisharp for S-Rank.
Let's face it; Bisharp is one of the most threatening Pokemon in this generation, and its mere presence on a team puts immense pressure on the opponent before the battle even starts. It's great against pretty much every team style; offensive teams can't switch in on Bisharp's extremely powerful Knock Offs, and must be wary of Defogging hazards away (which should always be used with Bisharp) because of Defiant. Sucker Punch also obliterates pretty much everything that might be able to outspeed and KO it, bar Fighting-types who resist it.
Defensive teams are in the same boat, constantly worn down by hazards and discouraged from Defogging as there isn't much a defensive team can do once Bisharp obtains +2.
Bisharp also completely fucks the most common defoggers. Latias and Latios are helpless against Pursuit, and the bulkiest Defoggers, namely Mandibuzz and Skarmory, are completely crippled when they take a boosted hit from Bisharp and they can't do anything back to it. The aformentioned Pursuit is also useful against Aegislash, and because Defiant effectively nullifies King's Shield's drop, it can spam Knock Off/Pursuit against Aegislash without worry. Because of that, Bisharp is the only Pokemon capable of trapping Aegislash.
Bisharp's presence on a team puts immediate pressure on the opponent, regardless of the team you have. Bisharp is one of those Pokemon that you absolutely need an answer to, and if you don't you'll get completely destroyed. It's mere presence completely discourages the use of Defog, as most Defoggers have no way to beat Bisharp without sacrificing general utility. Bisharp is a crucial member of Deoxys offense teams, and the unique and powerful pressure it provides against the opponent along with being absurdly powerful and difficult to counter makes up for Bisharp's flaws, making it worthy of S-Rank in my eyes.
I'm not the most well versed in OU and I probably could have been more elaborate on some points as I'm not as experienced a battler as most others, though I have used Bisharp pretty extensively and have knowledge of its capabilities. If you want to dispute me, go ahead but I firmly believe that Bisharp is one of the most influential and threatening offensive Pokemon in the current metagame due to its unique capabilities, probably only second to Charizard in terms of the offensive pressure that it can exert on the enemy. It definitely deserves S-rank.