In the first Civ game, the resolution of battles used a single turn probabilistic algorithm. So although the attack/defense ratio of battleship vs. pikemen was ridiculous, the low probability event of a pikemen win did happen from time to time... And battleship owners were pissed off accordingly !
Newer incarnations of the game introduced a hit point system with a multi-turn battle algorithm including an initiative factor - there are almost no more really surprising outcomes.
I believe the suprises were part of the Civilization gameplay, and they mirrored the real world suprises of the battlefield. They forced the player to have a deeper plan made so that his campaign works with no single unit being critical.