How about this; If you select multiple DSP of the same kind in the mixer, having a mode where changing a value would propagate that to all selected devices?
It might work like, multi select and then click on a ‘lock’ icon to lock the selection, then double click on any of the DSP to see it’s params normally.
Then, changing any of the params in the selected DSP would change that param on all.
Would be handy when you want to make global changes to, say, Gainers in the mixer.