Although Nina Simone may be a person with dark skin, it seems to be very racist for a lighter-skinned individual to not be allowed to play the part. If Zoe Saldana was interested in the part and was going to give a great performance, I don't think that skin color should have mattered and she should have been given the part.
Given the lack of representation for black women in Hollywood in general, this casting decision is deeply insensitive. Zoe Saldana is not a black woman, she is a woman of Puerto Rican and Dominican descent. Naturally, this has raised criticisms as there are innumerable black actresses who could have played Simone. That Simone was a militant activist for Black Pride only makes this decision more jarring.
Zoe Saldana is a great actress, and I'm sure she'll do a great job in this role. Having said that, if they had to artificially change her skin color to make her look more like Nina Simone, it begs the question: why wouldn't they just find an actress with darker skin to play the role? Surely there are plenty of good actresses with a similar skin color to Simone. This seems discriminatory to those with darker skin. On top of that, paying to change her skin color for every scene seems like a waste.
No, Zoe Saldana should not have been cast as Nina Simone in the upcoming movie "Nina" because she has fairer skin than Nina Simone and has to play the movie using black makeup. The directors of the movie should have sought out other successful black female actors that resemble Nina Simone more than Zoe Saldana does.