Fridge Brilliance: Caspian's ship is named "Dawn Treader". And the crew's journey is to ultimately find the Utter East that both their king and Reepicheep long to see... thus, when they finally arrive at the Utter East, the "Treader" quite literally treads the very Dawn of a new day.
While Coriakin himself turns out to be a Cool Old Guy, Lucy's walk up to the magician's study can get pretty unnerving—walking up a flight of stairs and down a hallway in complete silence, with strange carvings and paintings on the walls, doors that won't shut, and a minor Jump Scare in the form of the bearded mirror.
Values Dissonance: Many people today may not find too much wrong with Eustace's family, as was described in the beginning — though others may argue that the issue was with "faddism" as the likely motivation behind their lifestyle, rather than with their lifestyle per se.
Perhaps because they're moving closer and closer to Aslan's country, Narnia's equivalent of Heaven.
Or, to use a non-Christian parallel, they're on a vision quest.
Broken Base: This evokes this even more than the other two adaptations. Detractors don't like it because it adds an antagonist that didn't exist in the book, a Gotta Catch 'Em All plot involving swords and also a shorter running time. There's another subset that don't like it because it has a different director and therefore a different style from the first two. On the flip side, its fans argue that it needed some kind of narrative to help it flow better as a film (the book being a Random Events Plot) and they also enjoy the increased screen time for Edmund and Lucy.
Cliché Storm: The mist and sword plot created for the movie is this for some.
Will Poulter's portrayal of Eustace went down very well with fans.
Likewise Liliandil was warmly received, and the name she got in the film is taken as canon.
Fridge Brilliance: With Word of God confirming that the green mist was caused by the Lady of the Green Kirtle, it makes sense why she murders Liliandil in the next book. Liliandil was the one who told the Pevensies how to stop her first plan.
Fridge Horror: Lord Rhoop, the one found on the rock in the middle of Dark Island, has likely been constantly fighting his worst nightmares with no food and no rest for years.
Hilarious in Hindsight: Considering Disney and Fox are set to merge at the time of this writing, that would essentially mean all three Narnia films would be under one roof.
Ho Yay: There's a bit of it between Caspian and Edmund, though the film does point out that Caspian views Edmund (and Lucy) as his family.
I Knew It!: A small one. Fans expected that Ramandu's daughter would get Named by the Adaptation (as it had happened to a few other characters in previous films). Liliandil is accepted as canon.
Replacement Scrappy: Subverted. Though Eddie Izzard's performance as the voice of Reepicheep in the previous film was highly praised by fans, Simon Pegg's turn in the role in this film has been embraced with equal enthusiasm.