Sindh biggest weakness - small number of castles. 1 Starting and 1 bordering with MAD ghodids and Delhi. Barelly can recruit any army.
Makurian weakness - theri cavalry power is weak and dont have good armor, but 3 castles can provide enough troops.
Oman weakness - pooply developed cities, without Calula and ivory they "dont have" economy. Weak units, and Abbassids very likelly to attack. Seljuks/Ghazni also like war if you expand in Iran.
But a good player can win without recruiting units in castles, onyl starting stack, command on battle and mercenaries are enough and isolated position only secures your homeland.