Repositories within projects inherit permissions from project and global level, but personal repositories do not. To that end, it would be good to prompt for permissions during personal repo creation to choose an access level. This helps promote an open source culture within organisations and reduces friction when a personal repo is shared.
Currently, Stash doesn't have the ability to define default permissions for each created repository (this includes personal repositories as well) and project.
Would be good to have it, this will save a lot of time to define the permissions each time for new repository/project being created by having the a permissions scheme set one time, same like how JIRA works.