92 / 103 offenses are not the best but, who cares? you just get a free choice band/specs boost on any move thanks to protean, also having a life orb equiped greninja does almost the same damage as Deoxys-A
252 SpA Life Orb Deoxys-A Ice Beam vs. 0 HP / 4 SpD Salamence: 785-925 (237.1 - 279.4%) -- guaranteed OHKO
252 SpA Life Orb Protean Greninja Ice Beam vs. 0 HP / 4 SpD Salamence: 785-925 (237.1 - 279.4%) -- guaranteed OHKO
4 Atk Life Orb Protean Greninja Gunk Shot vs. 0 HP / 0 Def Salamence: 195-230 (58.9 - 69.4%) -- guaranteed 2HKO
4 Atk Life Orb Deoxys-A Gunk Shot vs. 0 HP / 0 Def Salamence: 227-268 (68.5 - 80.9%) -- guaranteed 2HKO
Using Alomomola (who loses to grass knot and hp grass) and porygon2 in OU just for greninja makes it more worthly of a ban, its fast, not the faster but still fast, even "fast" pokemon like thundurus and some 110 mons cant touch greninja without holding a choice scarf
"it losses to priority"
what kind of priority? greninja already resists bullet punch and talon cant even ko greninja if it isnt holding a choice band, mach punch users namely conkeldurr (who is terrible in OU) and breelom cant switch in also cant revenge kil if greninja stays and it already changed its type to poison/psychic and, dragonite and entei cant even ko greninja with extreme speed and greninja can ko back for sure
Also its irrelevant if it sucks or not in the ubers "tier"
i think comments like "hey its my favorite pokemon" "i use him on 10/10 of my teams pls dont ban" "smogon sucks just ban everything but bidoff and magikarp already XDD" "empoleon, cress and porygon2 can deal with greninja, pls do not ban" should not be counted
you know something its broken when u need around 3 mons on ur team just for him
Ban greninja, definitely
So let's start deeper discussion...
your arguments are more or less "Doesnt matter stats, he gets STAB on everything!" and "Too good coverage". It is certainly right... but let's think about it.
Most of Pokemon gets two STABS (some just one). Those are their stronger attacks that they can hit with neutral effectivness...
Greninja though, has STAB on everything. That means his low stats are comparable to something like Deoxys A using Ice Beam when Greninja uses Ice Beam.
but when for example Deoxys wants to hit something really hard and it is neutral to it, it's different. Let's take calc of strongest neutral effectivness...
252 SpA Life Orb Greninja Hydro Pump vs. 4 HP / 252 SpD Eviolite Chansey: 101-121 (15.7 - 18.8%) -- possible 6HKO
252 SpA Life Orb Deoxys-A Psycho Boost vs. 4 HP / 252 SpD Eviolite Chansey: 195-230 (30.3 - 35.8%) -- 36.7% chance to 3HKO
You can see... so basically you could say, Greninja is good as long as it carries super effective move against its opponent, because if it fails to carry one, then Greninja is pretty much
fucked done.
You started to comparing Deoxys A and Greninja, so lets continue, for example Garchomp, Deoxys doesnt have to use Ice Beam to wear it down. It may use Psycho Boost so if opponent decides to switch out, you have at least hurt anything a lot with his powerful STAB.
Greninja simply cannot, if it decides to go for Hydro Pump it doesn't even kill Garchomp, so it forced to predict the situation where Deoxys is simply not. Regice (I chose him because hes one of Pokemon that resists Ice Beam and is neutral to STABs of Greninja and Deoxys, so you could see the difference) can come onto Ice Beam of Greninja and take it, Greninja wont leave a scratch here, but Deoxys used Psycho Boost, because the Ice Beam didn't really mattered, so it would be better to use neutral move and it leaves the scratch on Regice quite noticeably.
My point is - yes, Greninja has STAB on everything but his STABs are not comparable to STABs of other Pokemon. His STABs on coverage moves outweights his not so good stats and his strongest STAB is not as strong as for example Gallade's Close Combat because it simply is not different from power of his coverage.
Greninja usually forces to some easy predictions, thats right, but there are still many situations you can switch out against Greninja and survive and possibly Revenge kill it.
THE OTHER FACT is that you say "Greninja gets kill everytime it comes out" - thats not right, it might fail to kill if it fails to predict and those are not rare situations, imagine using Ice Beam while Scizor switch onto him... then you did not get the kill because of prediction. And you cannot forget that same as you cannot switch onto Greninja reliably
he cannot switch onto anything as well... well actually to be honest, you may switch some Pokemon into majority of his attack, but with residual damage from SR and LO Greninja can basically switch into nothing.
That means BEST CASE SCENARIO revenge killer that gets 1 for 1, worst case scenario 0 for 2 (Scizor situation if you dont switch - predicting for example roost, using HP Fire, wore down by Bullet Punch).
So I cannot see really point why it should be banned.
You could as well consider that there is Mega Metagross and Slowbro, quite OP now, that Greninja can counter and those are really powerful threats.