News Flash, maybe you missed the memo, but anyone below top tier is pretty much worthless.
Being "high tier" in Brawl just means that you can place barely out of the money.
Link is worthless, but so are characters like Luigi, ZSS, Pit, Game and Watch, etc. These characters straddle high or mid tier but still can't compete. The game has 6-7 characters worth playing at all unless you don't mind placing 10-15th.
So really:
MK Tier:
MK
Worth Playing Tier:
Snake, Diddy Kong, Falco, Wario, Dedede, ICs, Marth,
Not Worth Playing
Pikachu, [Squirtle], ZSS, Olimar, Lucario, Pit, Peach, Game and Watch, Toon Link, Kirby, DK, Ness, Fox, [Ivysaur, Charizard], Pokemon Trainer, Luigi, Sheik, Mario, Wolf, Sonic, Link, Lucas, Ike, Samus, Bowser, Zelda, Yoshi, Jigglypuff, Captain Falcon
Ganon tier:
Ganondorf