Meta Knight? He does tons of damage, but nobody I know has figured out how to reliably KO with him. Also, while I think Snake is a great character, I find him lacking in 1v1. He's amazing in chaos 4 player FFA, but 1v1 many of his moves lose their effectiveness. I'd move both of these guys down a bit. I don't know if you intended this list to have rankings within the tier, but in my experience Meta Knight and Snake are probably High Tier, maybe lower for Snake if we're considering 1v1 only.
Your distribution seems to be shifted towards the bottom. In order of Top, High, Middle, Low, Bottom, you have 4, 6, 14, 7, and 5 respectively. If Middle Tier is to represent average, we should have an even spread about it. I'd say either move some of the Low/Bottom up, or move some of the Middle up.
Also, a note about Lucas. I don't know how many people have decided to customize their control setup, but there are some great tricks Lucus can pull with a B-stick setup. Retreating PK Fire, zap magnet, psi magnet/edgehog tricks, and other weird momentum effects. Other characters can do some weird stuff with a B-stick, but Lucus's tricks are far more pronounced. So I'd expect him to be a bit higher once people figure out how to put all this stuff to good use.
I just now realized that the two character's I'd move lower are marked with a D, and the one I'd move up is marked with a U. So yeah, overall I think this is an excellent layout here. Nice job with it.
EDIT:
On Yoshi. I found I completely kicked all my friends butts with this guy for about 6 rounds. Then they figured out how his strange air movement worked and I kept getting pwned. I think once people get some experience fighting against him he's much less effective. Maybe deserves Low Tier though.