As working with gsa I see lacking functionality of such a template projects with child - parent hierarchy.
1. I see nowhere ability to be able to use verified url from another project - and more important if I add a new url to that project they should also be added in all those child projects to post on it.
2. We could have also possibility to remove a verified urls eg by domain from all child projects - it's a very important in tier projects - what's a point in linking to a non-existing domain urls?
3. Regarding all projects. After an update comes a new engine and we have to enable it in every project separetely.