The Rambam (She’elot Utshuvot, § 36) was of the opinion that the repetition of the Amida should be nullified. He explains that after completing their silent Amida, many congregants would resort to idle chatter and would not listen to the Hazarat HaShatz, as is reuired. Furthermore, if non-Jews were to witness this, the Rambam says it could constitute a desecration of Hashem’s name as it appears that Jews speak during their prayers. The Radbaz (She’elot Utshuvot HaRadbaz vol. 4 § 94) writes that the community in Egypt-the Rambam’s residence at the time-did not accept the Rambam’s suggestion and the custom was to recite the repetition of the Amida.
Despite the importance of Hazarat HaShatz, the Rama writes (Orah Haim 124:2) that when necessary, such as in Minha when sunset is imminent, the congregation can pray out loud with the Hazan until the end of the Kedusha, and forego the repetition. Additionally, Rabbi Shalom Messas (Shemesh UMagen, vol. 1, § 37), Rabbi David Ovadia (Nahagu Ha’am, Tefilat Shaharit § 18) and Raabi Itzhak Hazan (She’elot Utshuvot Yehave Da’at) write that the custom in Morocco was that the Amida of Mussaf of Shabbat was not repeated because many in the congregation grew impatient from the long Shabbat prayer and would speak during the Hazara.
Summary: Although very important, the congregation can forego the repetition of the Amida when necessary.
When Can the Hazara be Omitted