yee - Broken or "too good" clicks to me when that one Deo-S set is destroying entire playstyles without anything special in the last 5 slots.
If you're implying that Deoxys-S can singlehandedly dismantle teams and that the 5 sweepers could be any run-of-the-mill Sweeper, you are terribly misinformed. There is a reason why Dragonite, Lucario, and Scizor are almost staples to this team, because they are fantastic sweepers in their own right, Deoxys-S or no Deoxys-S.
JellyOs - Okay, there's a reason Deoxys-S is a suspect. For starters it has the most ridiculous movepool in OU, in addition to Spikes, Stealth Rock (both rare for a psychic type) and even one of the most limited distributed moves in the game, ExtremeSpeed. His sets consist of near anything, to stopping any lead trying to set up rocks or screens with the fastest Taunt in the game, and after that Deo-S can set up rocks or dual screens on its own time while you switch and try to break past its bulk after the Reflect or Light Screen. I think Doexys should be banned not because of its game-breaking set up skills which allow nearly anything to set up after both Screens are up, but because it stops the viability of nearly any other dedicated lead. I think restricting what can even be used as a lead is ban worthy.
We don't ban mons because they have a rich movepool... (ie: Smeargle, Mew). The fact that Deoxys-S is almost restricted to its lead position makes it a manageable threat, imo.
Deoxys, in addition to being the game's best lead, is one of the best late game cleaners, or early game clearers. Say your MoxieMence sweeps damages a Scizor to 50%, puts a Gliscor to about 70%, and the Dragonie that revenged you took rock damage before it useed ExtremeSpeed. Also, let's just throw in a Tyranitar to that team. It sounds like a pretty strong core team to me. I send in my Deoxys after such a sweep, and instantly sweep what's left of your team using Superpower, HP [Fire], and Ice Beam. Now, why was I able to do this? Even if they had a Scarf Tyranitar? Well, it's because Deoxys is the fastest threat in the game, and can fully invest in offences without being hindered by a great need for Speed EV's.
In that scenario you portrayed, Deoxys-S will still be taken down by Scizor's Bullet Punch and / or Dragonite's ExtremeSpeed. In a metagame where priorities abound Deoxys-S isn't the most reliable cleaner, as I am experiencing first hand with my LO Deoxys-S. The fact that its best move has the "Draco Meteor syndrome," forces it to switch out, just to re-gain its special offense (although it is much less dependent on Psycho Boost than Latios is dependent on Draco Meteor).
The LO cleaner Deoxys-S still pretty much needs to fully invest in Speed to outrun crazy shit like Scarf Rotom-W and Scarf Landorus. Thus, these Deoxys-S can't even go +SpA nature to augment its borderline-good 95 offense. Its Atk is usually close to uninvested, supplying it a weak Superpower that barely OHKOs Tyranitar. It depends HEAVILY on its Life Orb.
The last reason I want Deoxys banned is because it throws off the speedy nature of the game. Since Gen III with the introduction of customize-able EV's, there have been speed tiers. Gen IV brought us the Choice Scarf to throw off those speed tiers, and make them more complex. With such a system, there are various speeds one aims for such as the 329 to beat positive base 100's. Sitting at the top of the OU Speed Tiers are Deoxys-S and Ninjask. One can function as a sweeper, and the other is a harmless Baton Passer. Deoxys-S throws off the entire Speed Tiers system, calls you a (BAN ME PLEASE), and then outspeeds your entire team with little speed investment. It does the same thing as Excadrill before it, throws off the speed system.
I guess Chlorophyll mons are the next to go out, because they are faster than Deoxys-S? Excadrill was not just fast - it was fast, strong, AND bulky. Deoxys-S is just fast.