From the Wiki: According to former Death Row Records chief engineer Rick Clifford, George Lucas was eyeing Tupac to star in his return to the “Star Wars” saga. Lucas had asked Jackson to ask Shakur to audition but due to Shakur’s untimely death the role ultimately went to Samuel L. Jackson. The character’s bald appearance could have also been an homage to Shakur.
I mean, his actual acting was fairly wooden as well. He’s a good actor, he was capable of much better in that situation.