Already mentioned, D.O.C.'s accident, leaving him voiceless.

Mos Def's forays into rock.

Ice Cube and Common going pop/Hollywood.

Mobb Deep and M.O.P. signing to G-Unit.

Anyone signing to Puffy after the Ma$e/LOX era.

Tribe's internal struggles. Seems silly on the outside looking in, though I know it's not so simple.

Nas spending his prime flirting with commercial appeal.

Outkast's label politricks after proving they can sell, going diamond.