TL;DR
Make a specific building, that barrels and un-barrels fluids.What?
This would be a specialized building, that can only barrel or un-barrel fluids. It would also have a generic recipe, to handle any fluid or barrel that enters the building, similar to how the recycler picks its recycling recipe. (When you put different items into a recycler it changes its icon automatically, showing what it's doing.)Why?
The UI is clogged up with barrel recipes, even without any mods that add fluids, or make more fluids barrel-able. It's also extra clicks, when you already need to lay down all the pipes correctly anyways. Plus, a generic recipe makes mods easier.