QUOTE:
what is the difference in that and arriving at a 2 runway airport with final reserve plus a bit in hand (providing the weather at destination is well above limits as stated in my previous post)?
You don't need to be an ex-forecaster [as I am] to know how quickly good weather and a forecast of good weather can go badly wrong.
This is especially so with the very poor standards of forecasting and observing to be found in more than a few countries.
I find the concept of using a second runway as a diversion hair-raising beyond belief.