For anyone else that gets stuck on this, this very cheap add-on has the ability to apply scale to both the armature and actions of a model - https://blendermarket.com/products/godot
Jun 30 2020
Good to see this has been reopened.
gaia (on irc) has created a python script which allowed for this functionality to work, with a option to set the scale of a skeleton and re-scaling a single or all actions with it.
If this would not work out as default functionality (which is fine), it would be nice to have a optional scale function.
The way fill's are handled (grid fill/beauty fill etc) is a good example of allowing for multiple 'default' functionality.