I guess one of the things I hate most about the unknown thing is that "unknown" usually boils down to "teen idol", in the case of Bryan Singer's Superman project, that would be 25 year old Brandon J. Routh of the TV soap opera world, a casting decision that does not instill me with confidence. I would much rather have had 36-year old Jim Caviezel as Superman, who was rejected by Singer for being "too famous" thanks to Mel Gibson's "Passion of the Christ"; I think an older man like Caviezel (who does not have the kind of unalterable persona that Tom Cruise has) could have brought my depth to the character than a soap opera guy. I also think Singer's getting pretty cocky if he thinks he can make lightning strike twice; I know the late Christopher Reeve was in his mid 20s when he played Superman in 1978, but Reeve had the benefit of being a Juliard trained stage actor. Most of today's brood can't even get into Juliard.
Tobey Maguire was not a complete unknown when he signed on to play Spider-Man.
2003's "Daredevil" would have sucked regardless of who was playing the lead character.