Turbine blade airfoils, film cooling systems thereof, and methods for forming improved film cooled components are provided. The turbine blade airfoil has an external wall surface and comprises leading and trailing edges, pressure and suction sidewalls both extending between the leading and the trailing edges, an internal cavity, one or more isolation trenches in the external wall surface, a plurality of film cooling holes arranged in cooling rows, and a plurality of span-wise surface connectors interconnecting the outlets of the film cooling holes in the same cooling row to form a plurality of rows of interconnected film cooling holes. Each film cooling hole has an inlet connected to the internal cavity and an outlet opening onto the external wall surface. The span-wise surface connectors in at least one selected row of interconnected film cooling holes are disposed in the one or more isolation trenches.