If you wish to look at real patterns then see the recently revised
CAP776 Global Fatal Accident Review 1997–2006. Note the dominance of flight crew related causes.
Fatigue does not rate particularly high (Appx 5 Table 1); however, the report does not dismiss it – “… care should be taken not to dismiss particular factors as being irrelevant to accident risk as there could have been an element of incomplete data. This was particularly true of flight crew related factors such as CRM and fatigue, which may have been subject to under-reporting by some agencies, not actually apparent to the investigators, or simply not thought to be worthy of inclusion in a summary report.” (Appx 1 page 3).
There might be greater benefit in getting crews to take the correct action, and improve flight handling and situation awareness, than looking for work or duty time regulations to cure safety problems.