Walking through the CSV import wizard shows how easy it would make the transition - until I got to status mapping.
Even though the space I am importing to has custom statuses (that are the same across all projects), my only option is to map is open or closed - that would lose all of my actual statuses. Where's pending? In progress? Under review? On hold? Or, if I don't map them they will be imported as new custom statuses that I will then have to reassign.
Mapping should match the Space's status.