The reasons behind the current workflow are basically:
- While creating projects is easy, confusing users with overlapping, poorly worded, undescribed, etc, projects is very easy as well. It is good to have basic quality requirements and a general overview of the existing projects.
- Cleaning up the mess created by problematic projects is not easy, and usually it's ungrateful work done not by the ones who created the problematic projects.
- Phabricator doesn't have a way to watch new projects being created (cf. T85183).
- Anybody in Project-Admins can create any type of projects without prior discussion except Tag projects (tags are usually not urgent, and they are the potentially contentious).
- New projects must be announced via creating a dedicated task in the project "Project-Creators" (Sprint and Release projects are exempt). After someone created the project, the person changes the status of the dedicated task to "resolved".
- Quality criteria remain the same (naming, description, etc).
- If a project is missing quality requirements or found problematic, a task can be created assigned to the creator of the project, describing what is missing. The project could be archived until its situation is clarified.
- If a project creator perseveres creating problematic projects, their Project-Admins membership may be revoked.
This is nothing else than the wiki principles applied to Phabricator project creation.