Never use Modest Greninja. Ever. Period.
Choice specs Greninja is bad because you already have power with STAB and high base-power moves. You're basically taking away your wonderful coverage and locking it into one move, which in kind of pointless...
Those calculations above are kind of meaningless because Greninja already gets most of those OHKOs and 2HKOs with Life Orb...
If you don't believe me, I can show you with my own calculations. In conclusion, stick to Special LO Greninja, please and thank you.
My effort to get a new discussion going: Substitute+3 Attacks Greninja
Greninja forces so many switches, so a Substitute set can let it predict less against stuff like Conkeldurr, and be less easily revenged by stuff like Talonflame, Breloom, and Scizor. It does have its downfalls, such as Losing it's health very quickly. So, a set would look something like this:
Greninja@Life Orb/Expert Belt
-Substitute
-Extrasensory
-Ice Beam
-Hydro Pump
Just a new idea to get the discussion going and talk about something other than Physical Greninja (which we were bashing back in December lol).
Why I shouldn't use modest? Aside from being slower than a Timid Keldeo, what are the downsides to running Modest over Timid?
Calcs for Specs versus Life Orb against 4SpD Venusaur with and without Stealth Rock.
252 SpA Life Orb Protean Greninja Extrasensory vs. 252 HP / 4 SpD Mega Venusaur: 244-291 (67 - 79.9%) -- guaranteed 2HKO
252 SpA Life Orb Protean Greninja Extrasensory vs. 252 HP / 4 SpD Mega Venusaur: 244-291 (67 - 79.9%) -- guaranteed 2HKO after Stealth Rock
252 SpA Choice Specs Protean Greninja Extrasensory vs. 252 HP / 4 SpD Mega Venusaur: 284-336 (78 - 92.3%) -- guaranteed 2HKO
252 SpA Choice Specs Protean Greninja Extrasensory vs. 252 HP / 4 SpD Mega Venusaur: 284-336 (78 - 92.3%) -- 31.3% chance to OHKO after Stealth Rock
Against CB/BD Azumaril
252 SpA Life Orb Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Azumarill: 265-312 (65.5 - 77.2%) -- guaranteed 2HKO
252 SpA Life Orb Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Azumarill: 265-312 (65.5 - 77.2%) -- guaranteed 2HKO after Stealth Rock
252 SpA Choice Specs Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Azumarill: 300-354 (74.2 - 87.6%) -- guaranteed 2HKO
252 SpA Choice Specs Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Azumarill: 300-354 (74.2 - 87.6%) -- 6.3% chance to OHKO after Stealth Rock
Against AV Azumaril
252 SpA Life Orb Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Assault Vest Azumarill: 174-211 (43 - 52.2%) -- 9.4% chance to 2HKO
252 SpA Choice Specs Protean Greninja Hidden Power Grass vs. 252 HP / 4 SpD Assault Vest Azumarill: 204-240 (50.4 - 59.4%) -- guaranteed 2HKO
Against Aegislash
252 SpA Life Orb Greninja Hydro Pump vs. 252 HP / 4 SpD Aegislash-Shield: 140-165 (43.2 - 50.9%) -- guaranteed 3HKO after Leftovers recovery
252 SpA Choice Specs Greninja Hydro Pump vs. 252 HP / 4 SpD Aegislash-Shield: 160-190 (49.3 - 58.6%) -- 69.5% chance to 2HKO after Leftovers recovery
With Stealth Rock, Specs give Greninja a chance to 1hko Venusaur and CB/BD Azumaril, something Life Orb Greninja cannot do.
Greninja with Life Orb is no doubt very good and hits hard while able to switch attacks, but it doesn't last long thanks to the Life Orb damage. Specs Greninja doesn't mind being locked into Hydro Bump and it hits like a truck.