Agreeing with Swamp-Rocket here:
Using Agility on the Special Side doesn't work out too well.
And to be honest, Special Variants of Lucario just cannot contend with other Special sweepers. Vacuum Wave is simply a bit too weak to alleviate his severe base 90 speed issue. Too many top threats such as Tornadus-T, Thundurus-T, Gliscor, Terrakion, Jellicent, Politoed, Dragonite, and Breloom are really able to punish Special Variants.
Physical Variants have access to Swords Dance and moves that carry higher base power.
Close Combat is 120 while Aura Sphere is 90
Extreme Speed is 80 while Vacuum Wave is 40
Extreme Speed has +2 Priority beating Techniloom after a Dance.
Vacuum Wave has +1 Priority; Techniloom can take a +2 VW and respond with Mach Punch for the OHKO.
Speaking of Agility, I really want to reiterate the potential Agility sets carry.
SD Variants lack coverage. Let's be honest. Base 90 Speed is pretty bad for a Sweeper (especially one that is frail; although Lucario packs a hell of a lot of resistances...but besides the point). If we look at this metagame, Lucario will be using Extreme Speed way more often that he will be throwing out Close Combats. Also since SD Variants have only one slot open for choice (SD, CC, and ES are pretty mandatory) coverage becomes an issue.
However, Agility fixes that issue.
With max Attack investments, Adamant Nature, and Life Orb, Lucario still packs quite the punch. Obviously he will not match the power of a +2 Lucario but with Entry Hazards and a worn-down opposition, that +2 is not needed.
Agility Lucario is able to free up a moveslot with coverage instead of utility (ES and BP).
Agility Lucario can run a powerful CC, Crunch, and Ice Punch.
Agility Lucario is able to outspeed many potent threats and loses to Rock Polish Terrakion and Landorus.
Obviously Techniloom still "looms" as a big threat but that's why a team is composed of 6 members...
If Lucario is given that chance to set up an Agility Lucario will practically outspeed everything including Tornadus-Therian and Choice Scarf Latios.
With Stealth Rock in play, Thundurus and Tornadus (therians) will fall indefinitely to an Ice Punch, as does Landorus.
Terrakion is demolised by Close Combat and Keldeo is a guarenteed OHKO with CC if it walks in healthy onto SR and a layer of Spikes.
Politoed will 100% be OHKOd by CC if it is Scarfed and SR is in play.
Specs variant must take SR and (1) spike damage.
Latios falls to a Crunch after SR.
Latias is 2HKOd. However none of her moves as a CMer will be able to OHKO Lucario.
In short, I just wanted to show that Agility Lucario is very viable and I feel it deserves a spot on the Smogon Analysis. (Which I'd be happy to write :D )
Edit: Oh my. This post is a little long ._.
tl;drThe first Paragraph talks about Special Variants of Lucario and the Second talks about the viability of Agility Lucario.