Permission overrides by Task Assignment

I'd like to suggest a permission override by task assignment.  I understand that folder/project sharing permissions to the users/user-groups inherits to the tasks inside them.

But for my user case: I share the Department folder with "limited access" to a large user group - so they can see what's going on and comment.  I also share "full access" to a smaller team who could do more things to the tasks/sub-folders/sub-projects inside this Department folder.

Every now and then there is a one-off task somewhere in this folder that I assign to a person that belongs to the "limited access" user group.  I would like him/her to have full responsibility to work on that task (similar to "editor" access level).

My suggestion is the action of assigning a task to someone would automatically grant "editor access' to him/her - overriding the "limited access" from the parent folder.  Of course, do nothing if he/she already has higher "full access" level.  This should also apply even if he/she did not have access to the parent folder. 

Currently, because he/she is not the the "full access" user group at the top level folder, the "limited access" is all he/she got.  Sometime, this may involve someone who does not even have access to the folder to begin with.  I know I could do better in managing user groups, but I forgot who is or isn't in which user groups.