Isn't Aura Sphere easy to shield against? It's pretty predictable, it may be slow enough to hit a spotdodger, but definately too predcitable to miss a shielding opportunity.
It really depends on how the Lucario is using it. In some situations, yes. In many situations though, no. A lucario who is planning on hitting your landing vulnerability frames should be experienced enough to time it so as you are unable to shield (actually not that hard). If a Lucario is SH Aura Sphering, the sphere may actually even shieldpoke off the top. If you are just standing there with a full shield and Lucario uses a sphere, he's most likely either too far away to be punished, or the sphere's recoil may push him out of danger itself. If he's spamming Baby Aura Spheres, then yes, it is quite possible to powershield them all, although the point is that it is still forcing reactions and slowing your approach. I could also use the powershield response against any projectile, and virtually any move, as well. Bananas, Marth's Fair, Lasers, they can all be powershielded reliably, so that throws that argument out the window. Note that these are only examples of a character that's on the ground, and thus able to shield. I could go on for days about its various uses in the air.
That's why you normally wouldn't use the fully charged attack. Most Lucarios I've watched usually use B only for gimping/spacing/etc., and close to never fully charge their Spheres unless they have an extra few seconds.
I actually had thought that most Lucarios should mostly be using fully charged Aura Spheres. Baby ones, while very useful for spacing against specific characters, should probably be used rarely to slow an approach and possibly tack on a few %, but the fact of the matter is that any situation a BAS would be used, a fully charged aura sphere would almost always be better (unless against a reflector or absorber when both characters are at a neutral position).
REALLY. You would suggest that Lucario's aura sphere is the best move in the game? An incredibly easy to dodge, slow moving, slow to charge, and overall predictable projectile is the best move in the game?
You obviously have not ever played a Lucario worth his salt. Aura Sphere is only easy to dodge when both characters are at a neutral position on the ground. There are many, many situations that can easily be forced by a Lucario in which he can use to safely and reliably connect with a charged Aura Sphere. Aura Sphere, while not as fast as Samus's charge shot, is actually not that slow, either. It seems to just be the right speed for Lucario's purposes. It covers ground quickly, but not too quickly that its immense size won't get in the way of a predicted roll or spotdodge, which is just plain nice. Oh, you just reminded me of something I forgot to mention: Lucario's Aura Sphere is the absolute easiest to charge offensive special in the game. (Squirtle's Water Gun allows him to maneuver as if he wasn't charging, making it the absolute easiest to charge special, but that's not offensive. =D) Due to the combination of its quick-release, the ability to keep his momentum in the air, the storing mechanism, it's very quick charge time, and various defensive options that can be immediately performed out of the (damaging) charge animation including airdodges, grabbing, shielding, and jumping(and by relation, aerials), I can safely say that if you can't find time to charge up Aura Sphere against anyone who isn't called Sonic or Falco on FD, you probably suck at Lucario. Lucario's aura sphere is only predictable if the Lucario is predictable. If the Lucario uses it properly to thwart horizontal recoveries, taking out landing frames, and punish misspaced moves, it can actually be very difficult to dodge.
Pikachu's QA is not the safest recovery in the game. He can be hit out of it, he can be reflected, and he can be gimped out of it.
I don't believe you have fought a good Pikachu if you don't seem to think that Pikachu's recovery is not safe. Pikachu's recovery has been safe since Smash 64, and with the addition of auto-sweetspots, it's even better now. It goes incredibly far on its own, can be angled twice to allow nearly impossible to predict recovery paths, can be canceled on the ground with a jump for absolutely no lag whatsoever, and is very, very quick. These five simple qualities make Pikachu's recovery definitely one of the hardest to gimp and/or intercept recoveries in the game, provided the Pikachu actually knows how to recover.
Marth's dancing blades doesn't have incredible range, the stall is not a recovery move in itself, it only shield pokes on a small shield, it does good damage, it shouldn't be used as a kill move, marth's grab is not very great, its fast sure, and it shouldn't be spotdodged.
The dancing blades are definitely long-ranged compared to most attacks in the game, the stall allows him to wait out invincibility frames as well as literally increase jump distance if used during a double jump, shield pokes pretty well with the down version on many characters, and can kill if neccessary on the more important lighter characters at not-that-extreme percents, and the spotdodge coverage is definitely a good quality for Marth, considering most of his attacks are simple, single sword swipes that would otherwise be rather punishable off of spotdodge or powershield.