To my knowledge, and I'm happy to be corrected, linked files such as pdf, dwg files etc. can only be re-loaded through the 'Manage Links' tool. This is cumbersome in my opinion, especially if small and frequent adjustments are being made to the linked files to affect the file's graphical display in Revit. An example may be the scale of hatch in a linked CAD file may need to be adjusted in AutoCAD to ensure that the hatch is reading appropriately when imported into Revit. Many of these adjustments can result in a lot of time being spent going into Manage Links.
Why not modify the interface whereby if you select a linked file in the model, in a drafting view etc, then a 'reload' button comes up in the ribbon. This would negate the need to keep going back and forth into the Manage Links tool to have the linked files refreshed.