Blue Marvel is from a great series created by Kevin Grievoux.
The character is placed in the backdrop of the Civil Rights era where because of his being Black he is asked to conceal his identity and exploits because of it. He is a high level herald who reappeared in the 616 and fought his archnemesis Anti-Man. Grievoux did a great job of displaying his abilities throughout the storyline.
I don't know why Marvel didn't capitalize on the character but it seems they've rectified this error with the coming of Marvel in MIGHTY AVENGERS.
Perhaps the name has something to do with it. Blue Marvel is pretty cheesy, especially considering the company name is part of the character's name.