How do you draw a line? You can't make a simple decision that is going to be correct for all pilots.
thoroughly agree - it would be nice if there was the ability to assess this sort of thing on an individual basis but it seems the only box the regulators have to put people in is based on age.
I have no problem with ageing pilots - I am one myself - but you need to mitigate the risks as you get older and keep to flights that are comfortably within your capability and with which you maintain good currency.
I would say the profile of this sortie would have challenged much younger pilots as well - unstabilised helicopter on a dark night with little or no ground illumination along with a vested interest in completing the flight.