I don't really understand the issue you faced. With 25 years experience I would say that End Conditions are rarely so simple and, if it is, it should be easy to manage with End Conditions. The first thing to say is that there is no Fill or Cut End Condition. User is the only one who knows if it is designed to be applied in cut or fill condition. We can imagine a new property cut or fill that would force the intersection with target from above or below. But there are a lot of cases where a "fill" condition is not targeting from above (or cut from below). Or cut/fill should be defined for each segment of the end condition. The good thing is that it is possible by checking/unchecking the "Find intersection" from point properties.
So think End Conditions as solution(s) to solve the interface between the origin and the target (surface, elevation, XY, ...).
So think End Conditions as solution(s) to solve the interface between the origin and the target (surface, elevation, XY, ...).