When the kohen would perform the service and atone for the nation all of the thoughts of those offering the sacrifices would fall on him. This is how the kohanim and the levi'im were able to know if these people had repented or not since they were exposed to their thoughts If the service had not yet excited them to repent and lit in their hearts a flame to return to H'shem, then the kohen would tip off the levi'im that the people had not yet repented. They would begin to play a sweeter melody to arouse a greater awakening that would bring those who had brought their sacrifice to repent before H'shem.
MiPeninei Noam Elimelech
Daily Halacha 3 Teves
To recite the bracha ha-tov v'ha-meitiv, there is a confluence of circumstances that need to occur, and thus, people who follow the stricter opinions rarely, if ever, recite ha-tov v'ha-meitiv.