I think any reasonably desirable date-driven notification can be achieved with the functionality that is now available 
I can imagine that some users may want notification some days before the due date, others when the date has passed, etc. so I suspect that any native due date functionality would end up needing to be configurable, at which point, it’s probably almost as easy to configure using automation (provided users can be helped to figure out how 
)
Maybe there is a future for ‘functional templates’ (not templates for types/relations but templates for combinations of fields/formulas/notifications) that serve a specific purpose like this, but which can be added to any type…
The stuff I did in relation to task dependency would be another example, maybe…