Sorting by columns: Some topics are suggesting DT provide more sorting columns and I think the case is stronger now that custom metadata fields are available. IMHO, It may be useful to increase but limit the sorting choice to two or three columns. However, anything more than that may create unnecessary confusion and users may need to reset the criteria and priority of sorting quite frequently.
How columns are retained in the group: currently DT3 will keep different column settings in different preview mode (None/Standard/WideScreen) even for the same group (if Retain View is unchecked in preference). To me, it seems more natural to retain the corresponding columns for the same group regardless of the preview mode. But I hope other users can share their experience/expectations on how columns should be retained in groups.