I think repeater lamps are invaluable, and I'm still amazed that North America is the only continent in the world that does NOT require them.
Puddle lamps are VERY easy to add to the 2008+ models.
The repeater lamps from the 2002-current Mountaineer fit perfectly on the flat area under the mirror housings. They're not flat, but close enough.
1L2Z-13368-BA is the part number (about $12 each), and the
WPT-489 wire/pigtail assembly (about $20) plugs right into it. Replace the amber bulb with a #168 or #W5W, and wire it to the interior lamp circuit.
These lamps also make perfect interior lamps in doors.