The new Gradebook is a wonderful improvement since it does allow for 10+ user defined columns to be displayed. The old Gradebool capped this at 10 columns, the rest remained invisible.
So the new Gradebook does unlock a number of potential applications. One of these applications is that we can use Canvas and the new Gradebook to handle Degree Project courses since we can create and all columns needed to assign supervisors, milestones etc in a user friendly way with all data available in a good GUI (the new Gradebook) for all teachers involved.
BUT: User defined columns do not scroll. This makes the gradebook very limited since we either have to use 4k screens or zoom out a lot in order to be able to see the whole Gradebook.
So I urge Instructure to take note of this limitation and make a fix for it since it hampers the potential of the new Gradebook.