This is a good strategy. Some members of MUA would like the Dashboard display to be guided more by which activities must be completed as part of course completion, but if I understand you correctly, that enhancement would already feed into the Action Events API. So the prediction would be: the student will finish the remaining required Dashboard events (at some undefined point in the future), and probably the number of actions completed will be the best predictor, though we may find that some actions predict completion better than others (I'm betting that submission of an artifact for feedback will still be a stronger predictor than reading a page).
There would be no "quarterly" or "tenth/decile" timesplitting. Could we set up a timesplitting method of "weekly"?