I really hope to see some comprehensive grouping options in the future,  A "group by fields" option would be a really nice start.  I'd like to see grouping options built into the same header bar as the source and sort commands.

 

Please note, I know there is a group command right now, but it is pretty limited, only works on one column, and doesn't work well with if a sub-item has a different value than a parent item.