>>428251421: the reveal was good, he had a decent and memorable movie to debut him and his overall character was appealing in that movie (and not annoying like fucking manaphy, jirachi, keldeo, hell even the mew in the same film.)
2: IDK if this is just me being an autist, but he came out sometime around after naruto was hitting its peak, naruto was a hit so kids and teens seeing lucario as this "ninja dog that naruto runs" that also was apart of the pokemon franchise at its peak might've pushed its starting appeal.
3: Over-representation, he was an ace of decent trainers in sinnoh, a unique egg mon in DPP to make it a more special encounter, used by the champion, featured in brawl, tons of merch cause of the film, and then carried on in smash 4, ultimate, pokken, etc as a poster child since his design just works for about everything (a fighter humanoid dog with dragonball Z powers.) unlike other designs which fall flat in some formats (like how braixen was very forced in pokken, and incinaroar is just.. bleh as a character in smash.)
