it is too easy to forget to change over well into the climb when things have gone quieter
That's why we have a climb checklist and a descent checklist, both triggered by TA/TL which is constant and standard instead of changing from location to location, just like the 10,000' speed reduction. KISS principle folks, why make things more complicated than they need to be? The US doesn't have altimeter setting regions either, you will always get the local altimeter setting of the airport or weather station nearest to you from ATC.