My 2 cents...
The thing I dislike most about D3 is the engravings errors (where it blanks all the keypads on a revision change)
I've done my share of Simple lighting, but to do a lighting program justice you need to have the "Last Button Raise/Lower" functionality, saving scenes, and setting schedules, is a must.
So now I use Home for my lighting, and shades.? Now I'm not a fan (yet) of home AV (and all their updates that only work after an update is done).
However, when you embed the smart graphics of the home lighting inside your great custom simple program, you get the best of all worlds.
Not only are customers able to customize their own scenes, I always tie the hard keypad buttons to those scenes, so the can actually change the levels (and loads) of a hard keypad press. Custom screen toggle let's you use "Room All On" (that doesnt have all room loads), and "Suite Off" (that turns off that room, and any other loads/rooms).
With the triggers to/from the processors, its not hard to have room on/off that could be on a Floorplan layout. Then you could always embed the smart graphics elsewhere for them to have the detailed control.