Prayers of thanksgiving and praise

When we think of gratitude and a lack of gratitude, the biblical scene that comes to mind is the healing of the ten lepers, of whom only one, a Samaritan, returned to thank the Saviour, worshiping and praising God in a loud voice (Luke 17:15-16).

Intercessory prayer

What do Protestants have against the intercession of saints? If, during their lives on earth, the saints interceded with God for their fellow men, after they’ve gone to heaven would they be wrapped in holy indifference? Or would their intercession continue?