Just because it has been in more number of battles does not mean that it's stronger than Base Greninja. Also the fact that as soon as It evolved into Greninja, it transformed into Ash Greninja in almost every battle, base Greninja does not have any battles in the first place.
All Talonflame did was to take out the first mon of a gym leader that's it. Beating smallfries does not mean it's stronger than Greninja.
When did i ever say number of battles?
All Talonflame did was to take out the first mon of a gym leader and thats it (LOOOLLLLL)
It literally tanked a Fire Blast from a Talonflame as a Fletchling, literally evolving to beat it. It tanked a Fire Blast from a Legendary and brought a hit in against said legendary(When has Greninja ever done those 2 things). It literally provided Ash to think of strategy to get rid of Spritzees Trick Room, it literally carried Ash and Frogadier through the match with Olympia (Without Talonflame, they would have lost), it brought a hit in against a Mega as a Fletchinder (When did Frogadier ever bring in a hit against Mega) and it never got down in a gym match without taking down another mon (Except for one) and never went down in the league without take a mon with it.
Then base Greninja's feats
Beating 2 of Ramos's mons (One of which was weakened) and defeating an already weakened Bisharp. Thats literally all the feats of base Greninja.
Looking at the entire line, its fact that Talonflame is way stronger than base Greninja (Talonflame doesn't need power-buffs to hit legendaries or Mega's, unlike Greninja).
Power wise: Base Greninja > Talonflame (On sheer feats alone, and this is a proven fact) > Ash-Greninja (Since i doubt both Base Greninja and Talonflame can currently defeat Mega's in base form, hitting them is a different matter)