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).