What hard is allowed to mean

Remove more clues and a grid does take longer. It does not get more interesting. You are doing the same three things you were doing before, just more times.

Because the solver already knows which techniques a grid requires, difficulty could be defined the other way round: by the hardest technique you need in order to finish. Easy grids fall to singles. Expert grids need the ones with names.

That is why an expert grid here sometimes shows more numbers than a medium one. The count was never the point.