In Pro, when recalculating a spatial index where the index had originally been set to a custom geography or geometry grid (in my example Geography Auto, 1028 cells per grid), Pro will automatically kick that down to 16 cells per grid. Pro should have the ability for the user to select Geography or Geography Auto, and specify the cells per object, which will have drastic effects on performance, as point, line, and poly feature classes are very sensitive to tessellation when they have thousands of features.