Yusaku Jon III
Chieftain
I would agree with the Doctor on the idea of a zone of control for forts, but that could just as easily be made up for in the early game by having cavalry units make the quick strike at barbs or enemies passing by on the adjacent tile and then retreating back to the fort to recover. If there are two or more in a stack, you can have your slower units knock off one or more and then return. Unfortunately, it looks like siege weapons useful only for weakening enemy defenses now and not for taking potshots at units passing within range (that gets done by fighters and bombers in later turns, it seems).