I dont see why not. Nobody says Luthor has to be an older guy. Hell, pre-Crisis continuity had Supes and Luthor at the same age.
A new take on Luthor as a young billionaire who made his money with social networking or other internet money like Google, and is seen as this nice guy, but is actually out raping horses and killing women.
People really need to stop Pariahring a film before it comes out.
As said before, the Batman franchise has been full of WTF? casting moments over the years that got ripped to shreds only to work out well (Keaton & Ledger spring to mind). And hell, everyone was pissed off with Katie Holmes in Begins, but then wanted her back when they cast Skeletors sister in the second one.
