Just an idea for enhancing character animation:
In editmode, when displaying selected bones - I think it would be a good idea to have a hierarchical display.
eg.child bones become a secondary tree branch which can be expanded or collapsed.
This would make the display and usage much easier to understand for characters with many bones.
A graphical example is shown below.
I would like to see a more heirarchical display too,
but my main fear is that it would create too much
clutter in the button window. A design like you
created would work great in the OOPS window
The idea I illustrated above was to simplify the window display, as, if you have a fully rigged character the bones display becomes extremely full. The idea of a self generating hierarchical structure would(I feel) greatly reduce editing time.