Problem: the current user roles are very limited to control structural changes on the spreadsheets, such as add/delete columns, add/delete rows & change columns titles, and letting the user modify cells content.
Admin / Edit - let the user to change the file structure and modify cells
** This creates chaos as anyone that needs to modify cells would also be able to modify the data structure (maybe unknowingly), so reports might not work, workflows might not work, cross spreadsheet checks might break etc DATA INTEGRITY IS AT RISK!
Viewer / Commenter - do not let the user change the file structure but do not let the user modify the cells content
** this denies the user to modify cell content, hence, not very useful for a big working group on which people have to work together and must modify cells - especially because comments, for instance, is not a very useful or practical thing to manage. Important info gotta go to cells!
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Solution: new role, Collaborator!
PROS:
this role lets the user to modify cells content but deny access to modify the file structure (add/delete columns, add/delete rows & change columns titles).
this prevents data loss, enables data integrity, better data management and security.
CONS: none!
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I think this would be an obvious thing for developers, but there it goes my suggestion ;)