Air carrier Captain reported new MetroPlex arrival charts in need of clarification of 'Descend via' clearance and early runway assignment. Current procedures results in high FMS workload in terminal area.

Narrative

Starting the arrival and decent; [flight crew] was given 'Descend via landing east'. We were confused about the route and lowest altitude to descend to. After talking to ATC and reading the note we found the change and did not have any issues or 'bust' any altitudes or route.[The] new format and new procedure with poor description and not noticeable change in route and lowest assignment [caused the flight crew confusion].Suggest the new format needs to be revised and more clearly noted what the route and lowest altitude is. The instructions need to be in a larger font and color to stand out. Also have the northern sections of ZZZ Center give the runway assignment in the clearance. They did not know what we were talking about until we got on with the next controller who explained it better. Also having to reprogram the FMS and altitude in the terminal area can cause confusion and error. Add 'pop up thunderstorms' in the terminal area the crews will be task loaded at a time when we need to mitigate errors.