many rule that if a minyan (quorum of ten men for prayer) for afternoon or evening services is held at the public menorah ceremony, then the place would be considered like a synagogue, and one would be able to light with the blessings.
Torat ha-Moadim 7:15; Yalkut Yosef Moadim, p. 204; Chikrei Minhagim, vol. 1, p. 205 (original edition).
Others, however, point out that the primary reason for lighting the menorah in the synagogue is in order to publicize the miracle of Chanukah. Accordingly, the same reasoning should apply to an even greater extent to lighting the menorah in a public place like the mall or city square. And the same argument can be made about many of the other reasons listed above. It is for this reason that blessings are recited at the vast majority of public menorah lightings, even outside of the synagogue.
See Responsa Az Nidabru 5:37, 6:75 and 11:32; Yalkut Yosef, Chanukah 671:10, quoting Rabbi Ovadia Yosef; Yad Natan 2:25; Mishneh Sachir 202; Beit Mordechai 41; Rabbi Yosef Heller, Haorot u-Beurim 721; Netivot bi-Sedeh ha-Shlichut 1:13.