There are several synonyms for the phrase "were requisite" which can be used to express the same idea in different words. These include "were necessary", "were mandatory", "were essential", "were indispensable", "were vital", "were needed", and "were required". Each of these synonyms carries a slightly different connotation, but all convey the sense that something is necessary or required in order for a particular outcome to be achieved. By using these synonyms, a writer can vary their language and avoid repetition while still making sure their point is clear and easily understood by readers.