Personally, that's a great piece of casting, Fishburne has a natural balance of authority and approachability that makes him a great leader figure. You may fear what Snyder will do with the Last Son of Krypton, you may wonder why we need another Superman origin story, but you really can't fault the casting so far.
It seems unfortunate to even address this but there will no doubt be a small, vocal number of fans who cannot comprehend a black actor being cast as a previously white character. We had a "Conservative group" calling for a Thor boycott because Idris Elba was cast in a role and the words "pandering" and "political correctness" have already began to circulate around the announcement of a half-black/half-hispanic Ultimate Spider-Man. People are very protective over their imaginary Caucasians, apparently.
Note that these characters are not defined by their ethnicity, they are defined by their character, so you can cast an albino paraplegic as a Terminator if they can play the role convincingly. I honestly do not think it's a strict case of racism (other than that Thor thing, those guys were super-racists) but a case of fanboys becoming fixated on the minor details. It is the same impulse that drives fans to obsess over the continuity of 20+ year old properties.
The Matrix star joins an already impressive cast for the upcoming Superman reboot, including Henry Cavill, Amy Adams, Michael Shannon, Diane Lane, Kevin Costner, Russell Crowe & Julia Ormond. We can only hope this modern take on Perry White can avoid any of those pesky phone-hacking scandals.