The Institute for Security Studies (ISS) in Pretoria published on 4 November 2013 a commentary titled "Al-Shabaab's Relative Strength Is the Real Threat" by Andrews Atta-Asamoah, senior researcher at ISS.
The author concluded that "Al-Shabaab may be weak in comparison with the capacity it had in the past, but it is not weak in relation to the frail Somali government and the huge internal vulnerabilities of countries like Burundi, Djibouti, Ethiopia, Kenya and Uganda."
While I agree with the above assessment, I think Atta-Asamoah is wildly optimistic about the utility of opening a dialogue with the "nationalist elements" of al-Shabaab. By his own account, al-Shabaab has been captured by the extremist elements of the organization led by Ahmed Godane. Al-Shabaab is not interested in dialogue and there is no one to dialogue with in any event.