Missing Char No: The char no is very important for the minified code to point at the exact statement as there is only one line in minified code. Even source maps cannot be helpful in tracking back to original line.
No Call Stack: The call stack is completely hidden from the developer so its hard to identify the functions flow. However there is a trick to extract stack in IE9 only.
Cross Origin Errors: These types are thown when some cross origin permission is broken. They are very common on pages with facebook like and google plus widget installed. For such errors window.error message throw a single message “Script Error”. As per stackoverflow post this behavior is intentional to avoid some security risks but its at expense of useful debugging information.
Most of above mentioned problems are roadblock in debugging production websites / applications. There is a need for better tools and libraries for the job.