Honestly, I never considered Black Mage an inspiration for CG. The "I hate my teammate" mentality which shows up in many of my characters (primarily Lance and Bill) is much older than Black Mage, and I think it's the main reason that people think of CG as a BM rip off. That or the fact that he's angry and likes to fight, which is rather different in execution.
CG is a bitter man, who enjoys combat and a little bit of torture if the victim deserves it, but is ultimately ruled by a system of honor. Black Mage is a violent evil man, who wants to kill everything around him, and is only stopped by his complete ineptness at doing said things.
CG is bitter because he feels that he has been shafted by the world. He has saved the world and gets little fame for it. Link on the other hand, is recieved as the worlds greatest hero. This is, in fact, done to reflect the popularity of their games. Crystalis never got any sequels, while Zelda would be single handedly carrying Nintendo if it weren't for the fact that Mario beat her to it.
He also doesn't get enough chance to shine in combat. He really likes defeating evil and showcasing his skills, and he never gets a chance to.
So I really don't think there is that much of a comparison. If anybody is a rip-off of Black Mage, it's Lance, and I don't think he is either.
Anybody who says otherwise will face the wrath of my rocket-powered lamppost!
Fear the lamppost!