Lucario

Lucario is completely unviable and outclassed in the metagame due to its unimpressive Speed, defensive ineptitude, and lack of distinctive advantages over its competition. Its Speed stat and horrific bulk leave it easily revenge killed by common offensive Pokemon like Latios, Alakazam, Keldeo, Garchomp, Terrakion, and Thundurus-T, which can take even boosted Extreme Speed, making Lucario unable to KO them even if it manages to use Swords Dance. It struggles to set up Swords Dance at all because of its defensive worthlessness and inability to force switches against many offensive staples and common defensive Pokemon, like Tentacruel, Gliscor, and Reuniclus. It's wholly outclassed by other Fighting-types like Keldeo, Breloom, and Terrakion, due to them all having more power, Speed, defensive utility, set versatility, and compatible team structures.