Dammit, we want to ban more shit that isn't even remotely broken?
1. Let's fix this by bringing Excadrill back down, please?4 OU votes, 1 Uber vote should not = Uber, especially when it has counters, checks, revenge killers, weather changers, etc. /rant
Stopped reading there, seeing as you clearly don't know that Excadrill has exactly ONE reliable counter, that has to pidgeonhole it's otherwise flexiable self into a highly specialised set, sacrificeing all offensive presence, just to stop Excadrill.
Not to mention it has about two checks [Skarmory, who can force it out ONCE, and Bronzong, who loses more often than not] and one Revenge killer that can OHKO it [CB Azumarill, no-one uses CB Conkeldurr]
And revenge killers aren't an argument when you have to sarifice something to get them in.
And the metagame changed between each suspect vote. So the 4 non-Uber ones are effectivly void.
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Anyway, on the topic of Dexoys-S. I personally do not feel that the issue is with hazards. Ferrothorn is capable of setting up the same hazards, at any point in the game, almost as easily due to his typing and defenses. So is Skarmory, and even Forretress.
I feel that the issue is with the Screens he can provide, and the ease with which Deo-S can set them up.
With threats in the metagame such as SmashPass, Multi-Scale Dragonite, Terrakion, Volcarona, bulky waters under rain, and many, many more, Duel Screens is a very potent weapon to have, especially when you're almost guarenteed to set them up early in the game.
A battle can be over very quickly just by Deo-S stopping rocks from going up with Taunt, and then sacrificeing itself to put up Screens so Dragonite can set up to +2 or even more without any effort whatsoever.
Obviously, Dragonite is the worst offender in teamstyles like this, with SmashPass being a close second, but the ease with which Deo-S can support the brutal set-up sweepers in OU, by setting up Screens with little to no way to prevent them, I feel breaks it in OU.
Deo-S can even run Focus Sash to guarentee both screens going up, and can probobly get away with it if you're running something like DD Dragonite, as all he'll need is three turns.
However, other duel-screeners can be prevented from setting up, or cannot prevent you from doing the same. Espeon is actually possible to outspeed, and dosen't have Taunt to prevent your own setup, for example. Bronzong is slow, and easy to taunt. There is no way to stop a lead Deo-S from getting up at least one screen.
Despite this, however, I am still unsure on which way I would swing with Deoxys-S' teiring position.