I used to post here back in '03-'04, then joined the Marines, but now I'm out and happy to be back on SHH. In a synopsis of the plot on wikipedia(if that holds any water), it says he's been hunted and has to heal old wounds. I think the 8 year device is smart just because Batman's probably been at least somewhat active despite being viewed publicly as a vigilante/danger, and he's probably lost emotionally and burned out. Then, he really has to get it together to fight Bane and "rise." Bruce Wayne could have also used those 8 years to improve on his company and public image a bit as well.