I completed it at Item Level 145 with all Level 58 gear obtained through side quests in Idyllshire. During the battle, I was expecting either Heustienne to turn into a dragon and fight her or some adds to appear because there was the Dragon Eye in the Level 50 Dragoon challenge versus Estinien. The only time that I actually felt threatened was when Graoully flew away and sent down some Snowcloak style icicles and their AOE was easy to avoid.

Bottom line: For someone who prides himself on playing the game with the Dragoon as my main, I was expecting a harder fight from the Level 60 Dragoon challenge compared to the Level 50. So, yeah I am disappointed about that.