I'd like to see supports that use a secondary extruder material only for the two closest layers that touch the parts, but the rest of the support structure using the same part material as the primary extruder. This would help significantly reduce the use of expensive/difficult support materials that have flexible, water-loving properties. The thin slivers (joints) of secondary support material could be dissolved and cleaned up more quickly, and the primary material remainder of the support structures will fall away on their own.