This section in the Workflow Run Crate profile mentions how to provide a general description of workflow inputs and output parameter slots (i.e. without any specific values). This seems like useful guidance to also include in the Workflow RO-Crate profile.

Workflows can have multiple input and output parameter slots that have to be mapped to actual files, directories or other values (e.g., a string or a number) before they can be executed. It is OPTIONAL to define such entities for a ComputationalWorkflow. If included, parameter definitions MUST be provided as FormalParameter entities and referenced from the ComputationalWorkflow via input and output (see the Bioschemas ComputationalWorkflow profile).

Including this in the Workflow RO-Crate profile would encourage workflow authors to follow best practices around declaring inputs and outputs. This information is already included in RO-Crates exported from WorkflowHub, so adding this section to the profile would reflect how it is already being used.