Bane may or may not be an effective villain (or certainly up to the standard set by Ledger and the Joker in the previous film), but I liked how he kept within the theme of the trilogy. I think as Nolan mentioned once, the trilogy is about the inner evil, willingness to do evil or corruption in Gotham citizens - this is what Ras was about, destroying Gotham because there was no redemption for its citizens. And there is a move to show these in different ways in each film. In the first film we have Scarecrow who manifests these inner condition through the use of the fear gas (and thus Gotham destroys itself that way). In the second film, we have the Joker who manifests this inner condition through anarchy. And in the final film, we have Bane who manifests this inner condition through the destruction of order.
Scarecrow believed the inner evil was, well, inside you and it could be released through fear. The Joker believed that the inner evil was induced by the societal order and "rules" as a result of conditioning and it could be released by breaking the rules, like he did with Harvey and attempted to do with the boat scene. Bane believed this inner evil had embedded itself within the social institutions (courts, prisons, businesses and banks) and that it could be released by destroying these institutions.
The problem is two fold, this theme isn't played strongly enough in the films (with the Joker's story the only one approaching perfection) and Bane's story becomes unnecessarily convoluted by concerning itself with the physical threat (a bomb) rather than playing up the overarching themes of what Bane is trying to achieve. I mean, let's face it, having a bomb with a countdown and making Gotham 'suffer' meanwhile isn't a good enough excuse to get a 'message' across, and reeks of the bad cliché present in every James Bond film ever. Bane should have also have been more of a villain in his own right, not just aligned with another villain seeking revenge. He breaks a few inconsequential necks and then defeats Batman once. But after that, it's downhill for him and there is no merit in his character walking around delivering monologues.