Lucario might of been a new pokemon, but his huge popularity in Japan got him into Super Smash Bros. Brawl. Which is something I didn't mind, except he replaced Mewtwo as a result.
Though he shared some of Mewtwo's better moves. I was happy to see the big orb back into Brawl.
Though Lucario was a lot of different than Mewtwo with other moves. He wasn't a bad character, but I still miss Mewtwo. I didn't even remember Lucario in Pokemon Diamond or Pokemon Pearl.
His final smash was a big laser beam, however it's weaker and slower than you'd expect. Also not terribly hard to avoid either.