There is a Shortcut: search in Timeline for Master Properties. Select all layers, then close and open with ctrl (on the little arrow) and you should see all Master Prop. with all options.
Big thumbs up for this - working with a lot of comps using essential properties and the time spent twirling is adding up os this would be a great productivity helper.
UU will expose some essential properties, but as far as I can see it'll only show modified ones, not any that are in their original state.
As the title says it would be nice to have an assignable keyboard shortcut to show/hide all the EG properties on a layer. I know the properties will be exposed on the new Properties panel in a future release but it's practical to also be able to open them on the layer itself. Right now you have to twirl down the layer twice with the mouse.