Greninja is something that we should wait out & see how he keeps his relevance, but he for sure is on the same level as Blaziken when it comes to popularity among the Pokemon Fanbase, which is nothing to sneeze at
& he has great odds to rise above Blaziken
As for the aggressive Lucario fans in the speculation days, can you really blame them, when the majority of Lucario supporters had to put up with crap of people that did not do their research. BW2 made it pretty clear who had the highest chance to make it into Smash between him & Zoroark. I was called a Lunatic on forums for pointing out Lucario had become the secondary Mascot/Face of the newer games, when Gamefreak brought him back in the spotlight, because he was everywhere
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XY also played it very safe with promoting to, because the most prominent Pokemon you see in Gen 6 media are Mewtwo Y, Charizard X, Mega Lucario & Sylveon, which all are new forms of Fanfavourites, showing kinda that Gamefreak will take its time, to create a new Gen Mascot