If you’d like to be able to make things “random” quickly for a complex structure of emitters, it’d be really handy to tie them all to a single Slider Control. (Also, if you dupe a system on multiple layers for compositing reasons, tying them to each other or to one master source.)
Unfortunately, the Random Seed slot is not keyframe-able, meaning also isn’t expression/pick-whippable to a Slider Control.
🙁