CR — CMMN does not include the notion of swim lanes

To clearly reflect the intent of a case style application - it is essential to provide business context. Central to that context is who does (or is responsible for) what. The existing model definition does not facilitate a clear graphical context to roles / swimlanes.
The absence of this visual and execution definition will likely severely limit the clarity and ease of use of CMMN thereby restricting it's utility and adoption.

Swimlanes is a new feature and it is out of the scope for the RTF

The introduction of swim lanes is a complete new feature that will require more work that intended by an RTF, and so it is out of the scope of the RTF. However this feature should be considered during the next revision of the specification.

Note that it is possible for implementers to add swim lanes to a compliant CMMN implementation, because the specification is silent about swim lanes.