Multiband min. 4 bands, much like Quadrafuzz but with the ability to load a plugin (or more) into each band.
Great suggestion! Quite a while ago I’ve build my own multiband chains by extensive routings to achieve exactly that but it was far from being handy and caused bad phase issues with some plugins. Can we have that automatically compensated, while we’re at it? 
I often only process the mid band, simply double the track use high and lowpass to get rid of the stuff I don’t want to be affected and add plugins to process. That is safe phase wise.
A dedicated plugin would be a lot more useful, but yes fully delay compensated is a must.