People who argue that Meta knight isn't broken either play as Metaknight, have never played a good Meta knight player, or both.
I'm REALLY glad that Peach is in the game as she is my main character. I never really considered her not making it, but I'm still glad she did. I hope I get to play the game though. I don't own a Wii U and am not buying it for one game.

-Strike
More info for people who are still skeptical that Meta Knight is broken:
"Meta Knight is notable for being at the top of the Super Smash Bros. Brawl tier list due to the very high speed of his attacks, having many attacks with transcending priority, many recovery options that grant him a long, relatively safe and unpredictable recovery, effective wall of pain options, KO moves that are both agile and reliable, and incredible matchups; Meta Knight has no overall disadvantageous matchups along with three other characters from the Smash series (Pikachu, Fox, and Falco), and currently only Pikachu is considered to have an even matchup with him."
"Meta Knight has been ranked 1st on the tier list since a few months after the game's release, although some players believed Snake was the best character. However, as Brawl's metagame evolved, his advantages in combat became more prominent, and Meta Knight mains such as Mew2King began dominating tournaments; as a result, Meta Knight was considered the undisputed best character, and has consistently held the top spot, commonly in his own tier above the rest of the cast. Meta Knight has won over three times more money in tournaments than the second most successful character, Snake."
http://www.ssbwiki.com/Meta_Knight_(SSBB)