Perhaps this already exists in some form I haven't yet figured out, but it would be great to be able to either wrap a formula with a try/catch (or in Excel syntax an IFERROR function).
This could allow additional logic to take place if formulas/plugins/workflows throw exceptions, or at minimum present a more user friendly error message than "...there was an error in North 52..."
Even if it were a separate field on the formula entity such as "Friendly Error Message" or similar. Ideally you could even configure this with multiple languages with the right language error message provided to the user based on their language (similar to how Portals does that fit Titles, etc)
If I've missed something existing please let me know