Grouping needs some love from Coda. One feature which I would like to see acting differently is Show empty groups toggle.
It would be really helpful if Show empty groups respects only the available options in the column which is grouped, not all rows in the referenced table
Current experience 
This would be helping me to:
a) improve UX with dynamically changing views in Boards and Cards,
b) minimize the number of Duplicate page buttons, and
b) significantly decrease the number of pages and tables views in documents