Yup, this has been a problem since at least 2010-2011. Running joke indeed, it looks horrible. And it's clear from their (WDW management) vacant expression, the "lights" are not all on upstairs (kudos if you get that Disney reference).
I don't know exactly how long this trim lighting problem has been going on for (I hadn't visited WDW for well over a decade prior to know exactly when this started getting out of hand), but it has gotten even worse since then. The only building at Grand Floridian with ANY working trim lighting was the Narcoosees restaurant, and there were still a great number out on that building as well. During my most recent October 2014 and April/May 2015 visits, quite literally ALL of the lights on the other GF buildings were out.
I'm not sure at this point whether all of them are burned out (which is possible given the lifespan of incandescents), or if they've actually intentionally switched them off entirely (which is also possible). I recall reading a comment some time back from someone in the know that they had been purposefully turning the remaining functional lights off to pinch pennies...
Oddly the lightbulb situation on Main Street is actually FAR better than it was a few years ago. I'm sure the fact that the facades were heavily refurbed recently have something to do with that, but i'm also sure there are lights that have gone out since then already given that they're regular short-life incandescent. So they may be replacing these more often than elsewhere.
The lights on the Crystal Palace facade were actually replaced with LED's at some point during the past couple of years (the rest of Main Street is still the old type of lighting however). Same goes for the bus stops for MK, they are also the LED variety and most seemed to be working on my last visit. The monorail station and ticket entrances at MK sadly had several dark strands however (these areas don't seem to have been replaced with LED's).
LED's are designed to last immensely longer than incandescents. They used to look horrible (the ones used on the overhead chandeliers in the Boardwalk Lobby for instance are the older kind and have an white-blue hue that are quite hideous), but there are a lot of newer LED bulbs that look fantastic. Panasonic have some of these over in Europe that were installed in some gorgeous historical buildings, they really nailed the color and I personally think they're at a point where they'd be great for replacing WDW trim lighting.-