I understand your perspective and we did consider the change in operation from 2.6 but think the benefits were worth standardising the controls to make PowerPoint and songs function the same. In 2.6 there was no cross-fading possible between PowerPoints and other items and the way they were controlled was completely different from songs.
So in 2014 F12 controls whether the presentation item is at the 'front' of the main display. F10 will fade to the curtain regardless of the item in front. The blue arrow button in the playlist will activate the item, starting a powerpoint and moving it to the presentation area. If the F12 was active then the will smoothly fade into view from the previous item giving a much more professional feeling.
We'll give some consideration to whether we can make any changes to accommodate your experience with the workflow however won't make any radical design changes to the user interface.