This patch basically adds the option to 'Reset' the active node via Back Space, as well as 'Copy Node Attributes' from the active node to all same node types in the selection via Ctrl Shift V.
Both new operators are based on this approach: http://blender.stackexchange.com/a/42338/3710. The code feels a bit "hacky" since it's simply replacing the active node by a new one. When calling 'Copy Node Attributes' Operator, it duplicates the active node and replaces all nodes (of the same type) in the current selection with its respective duplicate. Nevertheless the code works for all node types, regardless whether the nodes are connected and and it's nice to work with (IMO) as long as this is not implemented in C/C++.
A "reset to default" option makes experimenting with node setups much easier. Not only for large node trees, when it comes to eyeballing, from an artist point of view it's a common functionality in every node based environment regardless of whether it's Houdini, Nuke etc. to "reset" the node by one click (or even a group of properties of that node) in order to starting from scratch.