We just noticed that in the new look we can not see the datasets/flows if the workspace is set to: Members Can Only View content.
We are ALL admins, not members to the workspace, yet the entire group can not see them. If we toggle it to Members can edit content the sets/flows come back. If we turn off the new look, and leave it on Members Can Only View, we can see the flows/sets. Something is broken in the new look.
As a side note, when the new look was launched for reports there were similar errors and problems. I am not a fan of being used as a alpha tester without being asked, but as a content developer I am EXTREMELY unhappy with my users being used as Microsofts testers by way of the new look being turned on by default. If you are unable to launch a viable "update" to Service, at least have the decency to not force your users to devise work arounds.