This is a vital mod right here
But what if an advanced building (probably assembler) had crusher's stone-to-sand and imersite-to-powder recipes, to shrink gigantic imersite setups?

A good suggestion, thanks. I'll have a look - I've not encountered it yet in my base since I'm working from matter which skips the crusher stage (I think...).

This is a vital mod right here
But what if an advanced building (probably assembler) had crusher's stone-to-sand and imersite-to-powder recipes, to shrink gigantic imersite setups?

As of version 0.5.0, the advanced assembler can do crushing recipes as well (though this has to be set manually like a normal recipe). From version 1.0, there are some settings available that allow you to choose if you want to add the crushing recipes or just want the various stuff added to the chemical plant. Or vice versa, if you're so inclined.