I'd love the ability for ALL users to be able to create their own personal workflows in their personal space rather than having to either adopt an existing workflow that may not fit the needs of the user for the tasks/project they're managing out of their personal space. Maybe its not so much of creating a hard "workflow" as it currently exists in Wrike, rather maybe its simply having the ability to rename the buckets in the Personal space (much like MS Planner allows). Either way, giving users the increased ability to further customize their Personal space would add significant value to a stand out feature of Wrike.
This added ability for each user to customize how they manage their own personal work would allow a deeper adoption rate when onboarding new staff/departments into Wrike. As great as Wrike is with managing projects/tasks and communication throughout an organization/company, the Personal space is a MAJOR selling point when you're teaching folks about the system. The more individuals that use the personal space, the more accustomed and used to Wrike they get, and those habits of utilizing Wrike are created. Having the ability for users to have total ownership/customization options of their Personal space would be a significant value for every user that utilizes the Wrike platform.