Is it possible to automatically add a bottom of climb (BOC) and top of descent (TOD) point on the vertical profile and show it on the printed nav log to remind you where you need to start climb and descent to avoid controlled airspace / terrain etc ? Anyone else think this would be useful ?

On the Nav log you have column "Level". When you go to next leg of your route, you see at which level you should fly it, and it is a good reminder itself that you need to climb (or descend). If you add extra lines, in other words you create extra waypoints for every BOC(TOD), log will become too long and difficult to read.