The aura-reading Pokemon from the fourth generation makes a return from Brawl. Lucario is known for being a technical character in the roster and was made popular from Lucario and the Mystery of Mew. Various pictures show it in much higher detail, fighting the Yellow Devil in the Dr. Wily stage from Mega Man, practicing yoga with the Wii Fit Trainer, and more.
In related news to both Smash and Pokemon, this year marks the 6 year anniversary of Brawl, and the 10 year anniversary of Pokemon Fire Red/Leaf Green. This might be the potential reason of why Lucario was revealed this time. Only time will tell what character will be revealed next, but consider me interested in what comes next.