If this is a serious post, which is not easy to believe, then:
Mild = sufficient or inadequate, depending on context.
Strong = adequate or excessive, depending on context.
There is no "rule", feel free to make your own. It needs to be consistent, however, and that is a problem since what is mild in one reaction context will be too strong in another. Also note that many organic reactions can be done electrochemically, which means the requisite potential can be determined. Unfortunately, oxidizing agents aren't one-dimensional. That is, their reactivity isn't based simply on their ability to accept electrons. Instead specific (element or group) interactions (additions, abstractions, substitutions, rearrangements) also matter. For example a reagent which had only a moderate tendency to oxidize but had a high tendency to add a particular group might be considered a "strong" oxidant.