External credential provider for client-go
CronJob controller v2 is available through feature gate
PID Limits graduates to General Availability
API Priority and Fairness graduates to Beta
CSI Volume Snapshot graduates to General Availability
Non-recursive Volume Ownership (FSGroup) graduates to Beta
CSIDriver policy for FSGroup graduates to Beta
Security Improvements for CSI Drivers (Alpha)
Introducing Graceful Node Shutdown (Alpha
Runtime log sanitation
Pod resource metrics
kubectl debug graduates to Beta
Removing deprecated flags in kubeadm
RuntimeClass feature graduates to General Availability
Maintaining dockershim has become a heavy burden on the Kubernetes maintainers. The CRI standard was created to reduce this burden and allow smooth interoperability of different container runtimes. Docker itself doesn't currently implement CRI, thus the problem.
Dockershim was always intended to be a temporary solution (hence the name: shim). You can read more about the community discussion and planning in the Dockershim Removal Kubernetes Enhancement Proposal.
Additionally, features that were largely incompatible with the dockershim, such as cgroups v2 and user namespaces are being implemented in these newer CRI runtimes. Removing support for the dockershim will allow further development in those areas.