Given the number of opponents we had to work with, and with one having to be a mandatory "super easy" opponent, there had to be a difficulty gap somewhere. No matter where it was placed, some battlers were going to get caught in that gap.

The medium opponent (spider) was made a fair bit easier than your usual "medium" opponent to help out. This way newer/less-trained pets should have been able to beat one non-mandatory opponent, which they may not have been able to do otherwise :)