Currently, layer clipping is available at the DataFrame Properties level. That is ArcGIS for Desktop allows us to clip the data extents for the entire DataFramw by specifying the geographic extents in a number of ways (set of selected features is my personal favorite.) The DataFrame extents tab also allows for "exclusion" of some layers via a checkbox.
However, what happens if the user wants to clip different layers by different extents? Of if a clip extents should be shared by a layer group so that all layers in the group were clipped to a single extents definition?
My proposal is that the Extent tab be migrated from the DataFrame Properties to the Layer Properties. -- with all its functionality in-tact. (except for the "exclude" functionality.
Moreover, I suggest that new functionality such as "Adopt a Layer Clip Extent" can be enabled so that users can rapidly and consistently reuse/share extent definitions amongst layers.