I've recently started to incorporate FX Chains into my workflow. I do it not only as a tool to control multiple plugins at once with macro controls. FX Chain gives a chance to build a custom channel strip, where there's possibility to control multiple plugins in one window - without necessity to opening e.g. plugin A to use some high-pass filtering; plugin B to regulate attack, release, ratio, threshold parameters; etc.
Because of it I'd hope to see possibility to add more than 6 knobs and buttons to FX Chain in CbB.