I found another lolzy "guide" from another site about lucario, it's almost as "good" as the IGN video:
http://strategywiki.org/wiki/Super_Smash_Bros._Brawl/Lucario
Especially what it says about the D3 MU:
King Dedede
"This guy is lucario's worst nightmare. His fsmash can kill at 50% uncharged easily. Honestly, the best strategy here would be to just run from him and damage yourself by throwing smart bombs down to bolster your strength. The safest way to go is with the B button, aura sphere, to tack on damage. You can fight in the air, but do not come at him from behind because his powerful back aerial is fast, strong, ranged, and has high priority. You could approach him from above to use aura stomp (in the air), but you may risk taking up to 20% from his upwards hammer drill but suffer little knockback (Dedede-wise), which could be good, but he could also fake you out and hit you with another aerial. "