Lucario is a notable glass-canon - it is a beast when it comes to attacks (i.e; getting a STAB with an already 90 power'ed Aura Sphere that never misses), but the Steel-typing somewhat made it vulnerable. In Pokemon DPPt, a lot of strong trainers tend to have a Lucario in their team.
Also, when Lucario had been first shown, I remember that a lot of people had been delighted by the awesome design - not to mention Lucario's movie was also very popular. Even before Pokemon DPPt was released, Lucario had already a lot of fans. Not to mention the concept of Aura had been quite attractive in some way.
Still... do you think Lucario is overrated? Or did it deserve the popularity?