The tree view in Pending Changes gives a much better overview/visual structure to the things that were modified. However, per default everything is always collapsed. So for each new change one needs to click-open every single hierarchy level by hand, to reach the assets that were actually changed...

All other tree views (Items, Branches, ...) are affected similarly, and would greatly benefit from such a hotkey.

I suggest to use Alt-click, as for example, Unity uses that same method to selectively and recursively collapse/open subtrees.