Our company has been providing a final ZFW figure for years. I have always complied with it as it seems eminently sensible to do so. If the ZFW goes down by 10 tonnes on a 12 hour sector the typical fuel burn will reduce by around 4 tonnes, on the basis of 3.5% per ton per hour. By reducing the fuel I arrive at the destination with the same reserve as I would have done had I had the original ZFW. If it was safe to go before the ZFW reduction, why should aspersions be cast on the safety of the flight after the ZFW reduction and commensurate reduction in fuel burn. By the same token, if the ZFW increases, our system allows us quickly to ascertain the increased fuel burn and we load the extra accordingly. Are those posters who call the system wacky not increasing the fuel load when the ZFW increases? Perhaps they don't even notice.
Our company also keeps league tables but no-one is ever invited to tea and biscuits to discuss them, as far as I am aware.
On the question of alternates, we have normal alternates and what are referred to as 'Fairweather alternates'. If the forecast weather at destination is worse than 3K and 1000', we must select an alternate other than the 'fairweather alternate'. This alternate is invariably further away than the 'fairweather', thereby giving us at least two options in the event of a diversion.