I think it would be really nice if each component had a blend mode and opacity setting like adjustment layers in photoshop. Right now I do a lot of blends and this would clean things up a lot.
IMO that would work if all components in FF were 'modifiers' with a Source input. In FF, no all components work this way (Adjustments, Blurs etc do, Noises and Patterns don't).
Plus, it would add even more complexity to an already complex interface, which is undesirable.