/api/v3/ and /content/ could collide with a Live API
Live APIs can live anywhere and have hard-coded requirements. For example, pulp_ansible expects to server various urls also rooted at /api/v3/ because the Galaxy API works like that and it's also at version 3. I don't think any of the core provided urls formally collide with Galaxy urls.
The same problem can occur with the /content/ app.
Pulp could minimize these types of issues by rooting everything under
/pulp/ so the API would move to
/pulp/api/v3/ and content to