إما أن يكون الثاني أبلغ من الأول أو دونه أو مثله
The later expression may be more eloquent, inferior, or equal to the earlier one.
This classification evaluates the expressive result, not merely the chronology of two poets. A superior reworking is praised; an equal rendering does not display a special improvement; an inferior treatment is criticized.
Introducing different words is not sufficient by itself. The comparison must ask whether the thought is delivered with greater force, clarity, economy or expressive effect.