have you seen a good Lucario fight? at all? he's not slow, more like mid-speed, same with weight. His smashes may be slow but have ridiculous range, are tricky to dodge, and they're all extremely powerful. Also, F-smash is fast if spammed (seriously, as an Ike player, are you qualified to say lucario has slow smashes?).
Aura Sphere is as spammable as razor leaf, the blasters, the fireballs, and arrows. Not to mention it gimps recovery. And charged, it can be deadly.
Aerials have excellent knockback and three of them have potential to kill, four of them if you count gimps. Dair, Bair and Uair are all powerful and quick, Fair is fast and good for spacing and gimping, and Nair has good knockback for defensive purposes.
Edgehogging can be avoided due to the fact you can direct extremespeed in almost any direction. Besides, Lucario can wall cling out of his Up B, so if you're good with him you can easily recover.
of course, there's several more reason. Combos, grabs, good on air and land, survives against some of the best characters, etc.
Conclusion: learn more about lucario before you diss him. Personally, I wouldn't diss any character I haven't extensively used first. And yes, I did have a Lucario phase, but he felt too easy to use (even if I lost) so I got bored with him.