The runtime versions list in the new SwitchYard project wizard is not populated.
The problem appears to be related to the initialization of the Maven functionality within Eclipse. The SwitchYard tooling contributes a "custom" repository definition that is used when searching for available runtime versions. This definition is not loaded until the core Maven tooling is initialized, which is when the wizard queries for the available versions. The Maven tooling processes the contributed repositories asynchronously one second after the Maven plugins are activated.
Note, once the Maven plugins are active (workspace with Maven projects, Maven repositories view, etc.), the list is populated appropriately.