Aslan is more out of the picture in this one. In a sense, when Narnia fell to the Telmarines, the magic of the land, along with the magical creatures, receded into the woods and out of mind. The Telmarines became the rulers of the known land.

The Narnians accepted Caspian for several reasons--1. he was being hunted by the king, 2. he had historical treasures and knowledge/belief in real narnian history, and 3. perhaps most importantly to many of the more magical creatures (the Centaurs who were arguably the most powerful 'good' creatures) the stars foretold the coming of a new king.

Aslan is more distant because he has been discarded in a sense by the outcast creatures--Trumpkin the red haired dwarf is a big 'unbeliever' in many conversations (didnt translate it too much in the movie). The character of Aslan is more of a mystical and wild creature--not like a king that would himself, claim a throne and rule. Overall in the series, his purpose tends to be to inspire lower and weaker creatures to become great and rise to meet challenges. When other good creatures rise up and act as a nation of good, he does fight too.

The swordfight was a traditional type that relied heavily on rules and honor. Like a cage fighting match, there were breaks in the action to ensure the fighters fought at their best. The book went more into details about the rules that would have been tedious to see on screen.