But I'm still thinking that they should have made him a real black guy/alien. Superman is white as most of the Kriptonians we've seen then why can Icon be a black alien from a mostly black planet? I guess that if I was a comic writer and would have made Icon that way.
To paraphrase Icon, he's been a black man for longer than anyone else on the planet. 
I get what your saying, but the book works because Icon represents the history of African Americans, from slavery to the Harlem Renaissance to standing at MLK's side and on, while Rocket represents the reality of inner-city African-Americans in modern times.
Heh, Icon's real name was Arnus, and he looked like 'Kermit the frog with a better profile'.
The point to the character was that he had experienced slavery, Jim Crow and the Harlem Renaissance FIRSTHAND. Moreover, by the time Icon finally got back to his home planet a century later, his people has effectively cloned a replacement of him, rendering his return moot. During the time he was off-planet with Rocket he was replaced by Buck Wilde, Mercenary Man (Perhaps the funniest Luke Cage parody ever).
In retrospect, Icon was probably on of the better books published by Milestone. Milestone main failing (thru no fault of its own) was that it came out during the same time Image and Valiant did.