I think its more important that they found a solid actor to play the role rather than one that has similar features to Tupac. I'd also prefer a younger less known/recognised actor to play him as that will bring a fresh view rather than thinking oh thats Mekhi Pheifer playing Tupac, know what I mean? I wouldnt mind at all if they based the movie on Tupac but changed the names, as long as the movie is directed well and has great acting.
A good director I think would be Norman Jewison, he did The Hurricane and seems like he'd keep it true and entertaining. Or you could always have Brian De Palma and have a Scarface type affair haha..
Like I said as long as it has good directing and good acting and the scripts hot it can be anybody, I'm not fussed.