Evaluate and (Gradulate or deprecate/remove) experimental features

[ahrtr]

What would you like to be added?

There are lots of experimental features/flags, but they haven't been promoted to stable features, not deprecated for a long time. We should evaluate them one by one, and then (graduate or deprecate/remove) them.

Why is this needed?

graduate or deprecate/remove experimental features

[jberkus]

When we get to making a survey, please request on k/community. I'll help with it.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.