Suggestion: Diminishing returns in arena for beating the same person, or being beaten by the same person. It is quite ridiculous to be able to gain 200 points or lose 200 points by the same person in a single 30 minute period. It leads to wild swings in rank. I envision a penalty of 1 point per additional win/loss (10 points first win, then 9 for second, 8 for third, and so on, so that zero points are won/lost by the 10th attack on the same person). This would reset every time rankings are updated.