Shaikh Uthaimeen, may Allaah have mercy on him, said, “I advise our brothers, the Imaams [who lead the prayers] not to prolong the Qunoot supplication [in witr] to the extent that it is difficult for the people to bear, and they use unusual, rhyming supplications–[whereas] the best speech is short and concise, and it is better that a person does something in the legislated fashion so that the people do not become fed up.”

Fiqhul-Ibaadaat, p. 291.