Like any genre since the advent of recorded music, rap has suffered its share of onstage bombs, performers who shout sloppily over pre-recorded tracks while aimlessly sauntering back and forth. (This was no doubt exacerbated by the fact that bigoted venue owners and promoters wouldn't book rap shows and tours until the late '90s, meaning that MCs had little incentive to step up their live game.)
But in 2013, saying that live rap shows can't be good is just lazy. Even for the "rappers don't play instruments" crowd: The Roots are widely recognized as one of the best live shows on the planet, and many rap acts have taken their lead by incorporating the explosive, loose energy of live bands into their show.
Not that they necessarily need it. As anyone who saw Run-D.M.C. in their heyday, or even, believe it or not, Fresh Prince and Jazzy Jeff in the pre-Fresh Prince era (check "Live at Union Square November 1986"), can attest, a well-coordinated DJ and MC team can be just as powerful. And nowadays, with rock and pop stagnating commercially, rappers are the ones pushing the envelope onstage. Here's Kanye describing his Glow in the Dark tour on his much-missed blog:
ROBOT DESIGNED BY ACCLAIMED ARTIST CHRISTIAN COLON ... CREATURES BY THE LEGENDARY JIM HENSON'S CREATURE SHOP ... LIGHTING BY MARTIN PHILLIPS AND JOHN McGUIRE, RESPONSIBLE FOR LAST YEARS FESTIVAL ANNIHILATOR, DAFT PUNK'S PYRAMID, POSSIBLY THE GREATEST LIGHT SHOW OF ALL TIME!! ... WE'VE GOT HOLOGRAMS SHOT BY HYPE WILLIAMS!!!
For once, he wasn't exaggerating.