- It doesn't follow the "normal" OSS process of submitting pull requests. Their CI/Repos/Bug tracking systems are different enough that a lot of people probably don't bother trying to contribute
- The docs are not great and sometimes do not get updated.
- You basically have to run the control plan in containers to make it realistic to deploy. Kolla-Ansible and Openstack Helm are pretty good here
- The APIs are pretty slow since they're all in python
- You also have to deploy Ceph to get storage, which is itself an entire beast