>>57990441Lucario and Charizard are much more widespread Pokemon so it's easier to get away with it.
For better or for worse, Pikachu is way too tied-up at the hip to Ash, and Red for that matter. People want to avoid such baggage.
Ironically enough, I think Anime Lucario always being so BORING, literally only Cameron's Lucario has a personality, all the others are just 2cool4school serious no fun allowed dudes, so people think "I can do Lucario better, I can actually give it a personality" and the saddest part is that the bar is extremely low so it's something anyone can do without much worry.
Add Aurawank and that's another plus to having a Lucario in.
Charizard despite being so popular, it IS the species as a whole, there's no THE Charizard. Ash's Charizard got booted out and never returned, Alain's lives in infamy, no one cares at best and hates Leon's at worst. And then there's the general shafting of Y for X. There's not been a "Charizard" that has been "handled well" so just like Lucario people think they will be the ones to do it.
The real odd one out of the equation is Greninja. Genuinely cannot think of a single relevant fic that's got a Greninja as part of the main cast. Guess it goes to show how deep the stain the Kalos League left runs.
