Mixed Lucario (Experimental)

Did you consider how you'll deal with the flying intimidate users? Salamence, Gyarados, etc. You're stuck with using Psychic vs them.

Ghost/Psychic types may be a problem too, as the levitation users will dodge all but one of your attacks (if its a ghost) and the psychic types will prove tricky. Things like Slowbro or Reuniclus will hard counter you without Crunch. Gengar or Rotom formes will have similar issues for you.

You might want to use Crunch in place of Earthquake. If you're staying in vs Heatran, you have Aura Sphere for Super Effective damage. If other Fire-types come in, I'm sure you would be able to handle them or switch. A Dragonite is also gonna be tough for you to handle.

 

No pokemons perfect, so youll always have trouble with something. I think Ice Punch instead of Extreemspeed would pay off. While you lose that speed advantage, an ice type attack would wipe out Ground, Flying and Dragon types, which would mean your only real threats are Ghosts, and anything that can dodge your Earthquake. With the Life Orb, most Pokémon wint need a 2nd one of those.

 

I would personally have PlusSpeed Minus Defense as the nature. Speed is so important in the meta game. IMO, this Pokémon is more of a "finisher" Than actual attacker. I would have a stat boosting move such as Swords Dance, and cut Earthquake. But this is my opinion.

 

I'm pretty sure naive is +Spe +SpD, so it's what you said only specially. And he needs the coverage. Besides, a 4 attacks moveset works with any choice item, unlike one with a setup move.

 

Mixed Lucario isn't too uncommon!

I'm unfamiliar with Gen V's biggest threats as I was a Gen IV junkie, but typically Psychic isn't the best option. Dark Pulse may be able to broaden your horizons but it's entirely up to you and as I've admitted, I'm not up to the recent metagame ^^;

Like aforementioned as well, Ice Punch may be in your better interest over ExtremeSpeed, as a Naive Lucario should be able to outspeed a number of its opponents without priority.

 

you might be better off running a set such as:
Lucario@Lucarionite
Ability: Justified/Adaptability
Hasty nature
176atk/80spa/252spe
- Close Combat
- Dark Pulse/Flash Cannon
- Bullet Punch/ExtremeSpeed
- Aura Sphere

It's probably best to run Dark Pulse/Bullet Punch as with Adapatability and Bullet Punch you get an 80 bp Steel type Priority move which is even better than E-Speed because you can hit those Fairy types on their weak defensive side. Dark Pulse also guarantees you can catch Aegislash no matter what seeing as how it doesnt make physical contact for your attack to be lowered. Adaptability Close Combat and Aura Sphere are insanely powerful and will take care of any Breloom/Conkeldurr/Heatran/Ninetales problems you might have. Honestly if you're looking for any good mixed attacker Lucario, making it go into its mega form is probably your best bet because not only does it match the power Life Orb gives but Adaptability increases the power of your Fighting and Steel moves to be extremely powerful.
You could also try 80atk/176spa/252spe if you so please.
edit: just realized this was posted before gen 6, which in such a case then ignore this o.o