I hope your students (and you!) are enjoying A Dicey Situation.
After looking at the early submissions, the most common error among those who attempt to be systematic is failing to recognize that Player A rolling a 6 and Player B rolling a 3 is a different outcome than A rolling a 3 and B rolling a 6. That oversight does lead to the same conclusion regarding which player has the advantage, but it neglects 15 outcomes.
It will also have implications for creating a fair scoring system in the Extra.
Let me know if you have questions or would like an issue addressed.
Thanks for your efforts in teaching problem solving.