Vendee -Not sure where you get your information on the Harriers being 'clapped out' ! A lot of the airframes had far fewer hours on them them than the Tornado fleet and in many ways were superior in terms of reliability and future potential.
Regards the AH-64 Block III -this has always been a racing certainty . The vast majority of 'D' operators will update to the 'E' -whether with new build or reworked 'D's. Some of the desired mods are the engine gearbox improvements and modifications to the mrg and improved avionics.
The airframes themselves can go straight into the programme -there is no need for new aircraft . Indeed many 'D's are ex 'A's that are gutted and reworked .
Its nothing new and is very well conceived.