I shouldn't be surprised this thread keeps continuing. Ahem, Anwar have you been reading Batman, Inc? It's exactly about Bruce widening his horizons. As for why Batman doesn't kill Joker...I guess you haven't paid attention to the last twenty or so years worth of Batman comics: Batman Does Not Kill. They've done stories were Bruce has seriously contemplated killing Joker but ultimately chooses not to. I laugh at building a better cell comment. Arkham Aslyum has been continuously upgraded over the years to essentially be inescapable and yet rouges continue to do so. There was an issue of Gotham City Sirens recently where Harley was able to break into the Aslyum.