According to THR, although Warner Bros. and Zack Snyder "toyed" with the idea of hiring an older actor to portray the version of Lex we're most used to seeing, they ultimately decided to go with a much younger take -
"more in line with several recent graphic-novel and TV incarnations, in which he is a childhood friend of the young Man of Steel." That seems to confirm that they'll be taking the
Smallville route when it comes to Lex and Supes' relationship anyway. The site also reveal that
Girls' Adam Driver was approached to play the role (we had thought he was up for Batman's former sidekick Nightwing) but had a conflict, and the previously named Joaquin Phoenix passed. It seems that Bryan Cranston was never so much as in talks though, as sources say that a wide net is not being cast when it comes to filling the various roles, with actors from a "narrow shortlist" being targeted. More at the link below.