Is it appropriate to include class presentations in CV?
I feel your CV is already quite strong based on the fact that you have topped in both the mentioned bachelor and masters degree. Adding this detail in the achievement section would be sufficient to make the CV look strong.

However, I feel that presentation and discussions are integral part of the degree in Arts itself. So, by adding these details (which are trivial in some sense) would not help much. However, you could probably mention something in your strength section of CV under "Presentation skills", "Discussion skills". You don't have to mention the topics that you have presented, as these would look like junk to some people.