Usability - Optimizing task completion

[Quantum7]

I can use SHIFT-C to instantly flag 1 or more tasks as Completed (more accurately to set the flag of the task to completed).

However, I'd like the "Date Completed" (if present!) to be automatically filled with the current date if I check the Completed flag. This would save alot of mouse clicks while completing tasks (and is in most situations logical ).

Note: I realize this implies a logical relation between attributes that doesn't necessarily exist for every type of item / might not always be desirable.

A configuration option or even a generic mechanism to deal with these kind of situations does seems desirable though.

Possible Idea:
Maybe the mechanism for this feature "Title attribute based on other attribute values" could be generalized to deal with these kind of feature suggestions (that way the way it works could be info item type specific).