Yeah, I agree that Lucario is extremely good. The buffs you get from Aura are insane and if you survive long enough, you can kill at crazy early percents with the side B and pretty much any smash. I don't think he's as broken as some people say he is just because Aura is really the only huge thing he has going for him (a lot of his moves are rather lackluster without the aura boost), but he's certainly near the top.
The biggest thing I'd argue with on that tier list is Bowser's high placing--and that's coming from someone who uses Bowser as a secondary. He's fun and all, and has a couple crazy strong options (like one of the best anti-air up smashes in the game and a hilariously long-reaching forward tilt, along with the Bowser classic up-b out of shield) but he really struggles when it comes to approach options and matchups against other top tier characters, most notably Sheik and Rosalina. Sheik straight outspeeds everything Bowser does and can combo him like crazy, easily dancing around most of what Bowser can do, and Bowser just has no way to consistently get around Luma, making his already crappy approach options nonexistent.
I also think Sonic should be closer to the top--a good Sonic player (watch 6WX) can do some absolutely insane stuff with the side-b and the generally fast moveset that Sonic has. The fact that the side-b can be cancelled with a shield during charge up OR a jump at any time means you can scoot around the stage safely and your opponent has to keep guess where you're going next. That combined with spectacular grabs and a very versatile aerials and Sonic is one of the best characters in the game.