If you define your round robin as "100%" (by which I assume you mean every node with mine permissions has to participate in the cycle), by setting the mining-diversity to 1.0, then by definition it's not possible for any node to be skipped in the rotation. Relying on block timestamps as a way to determine if it's permitted for a node in the rotation to be skipped is an interesting idea, but would have to be considered carefully from a security perspective.
