People here are overestimating Al-shabaab. They are militia, same as everybody. The question is do those who oppose Al-shabaab have the will to defeat it? Galmudug is soon Inshallah Al-kebab free. It will be a matter before this causes a domino effect.
I actually think Al-shabaab will fracture in qabiil lines if Amisom leaves. A lot of qabiils support Al-shabaab because it gives them protection and also ability to gain power and firearms. Its a tool for them. Qabiils would not support other qabiil overruling them, thus Al-shabaab fracturing. It would be a good opportunity to beat them.