Actually it does report an error about this:

ERROR: [DClu0004 from diagnostic NodeDefinition@openshift/origin/pkg/diagnostics/cluster/node_definitions.go:118]
       There were no nodes available to use. No new pods can be scheduled.

Do you think there would be a clearer wording needed?

(In reply to Luke Meyer from comment #1)
> Actually it does report an error about this:
> 
> ERROR: [DClu0004 from diagnostic
> NodeDefinition@openshift/origin/pkg/diagnostics/cluster/node_definitions.go:
> 118]
>        There were no nodes available to use. No new pods can be scheduled.
> 
> Do you think there would be a clearer wording needed?

Oh, saw it -- I should have searched with strings "Unschedulable", "scheduling" ,"disabled", "unable" and unfortunately didn't note the line. And generally speaking, the current message is ok, but I like the style of DClu0003  much more, since:
1) It described very clearly what the current state is and it's root cause
2) It gave out exact command as the solution to resolve the current risk
3) It pointed out very clear on what will happen if I keep in this state


WARN:  [DClu0003 from diagnostic NodeDefinition@openshift/origin/pkg/diagnostics/cluster/node_definitions.go:112]
       Node host-8-174-87.host.centralci.eng.rdu2.redhat.com is ready but is marked Unschedulable.
       This is usually set manually for administrative reasons.
       An administrator can mark the node schedulable with:
           oadm manage-node host-8-174-87.host.centralci.eng.rdu2.redhat.com --schedulable=true
       
       While in this state, pods should not be scheduled to deploy on the node.
       Existing pods will continue to run until completed or evacuated (see
       other options for 'oadm manage-node').

Changed to be a low severity enhancement request.