With a few weeks of adjustment period over, following the inclusion of Jade Thorn Rose into the Imperial Family as Elric's Imperial Consort and the kingdom officially becoming a territory, Elric felt that it was time to let all of the current Voices of the People step down, and new ones to take their place. Many of them had served for several years, thanks to the people of their respective territories re-electing them a few times because of the dedication they showed.
It was not to keep the current Voices of the People from gaining favor with the people, and thus gaining a bit more power. It was the furthest thing from his mind. As it was, he wanted to give a few of them even more athoity and permanent positions that served the people in a different way.