I just started playing with creating custom Action Types.  I’m not quite sure how to leverage the feature just yet. My first attempt was to create a type called “Personal To Do” but the options available were not what I expected.  

1. We should be able to require and/or disable the description, priority, site, asset, and labels.
2. The permissions for “Detail Fields” (who can edit them) should no longer be a global setting but rather be per Action type. I may want types that restrict editing to only managers.
3. The “Action status” should no longer be a global setting but rather per Action type.  I may want additional status options for some types and very few for others.
4. The “Priority-based due dates” should no longer be a global setting but rather per Action type. I may have types that are more severe and need a shorter default timeframe.
5. Action Access should no longer be a global setting but rather per Action type. To me, this is very important to be per type.  For a personal type action, I don’t want other people to see it. For site-wide actions, I want everyone to see it at that site. 
6. Labels should no longer be a global setting but rather per Action type. Different labels may apply to different types.

Maybe I just haven’t understood the purpose of Action types + Action labels, but this is what I see in my first time trying it out.