Clearly defined, dedicated buttons (no shifting) is always the way to go with non-technical users who maybe using a control system under duress.
Actually, I know some users who will ONLY use a control system under duress.....
I like the looks of the new keypad also. Of course, I've said I didn't like the looks of the original since the moment I saw it x years ago.
I have very mixed feelings about losing the two function keys. On one hand, whoopty-do, it's only a function key and can be replaced with any of the several good suggestions already mentioned.
On the other hand, having different keypads WILL create some problems. HAI used to have a large keypad (IIRC it was called the "universal" keypad), that had nickel sized buttons instead of the pencil erasor sized you normally get on alarm keypads. The older folks loved it, as it was large and easy to use, but cost significantly less than a touchscreen. However, it differed from the normal keypads as it had two additional "scene" buttons. Invariably whenever I had a mixed keypad installation, after explaining the keypad and all the buttons, I would get asked where the "scene" button was on the other keypads.