As for my statement about people not needing a GAC for sun due to medical reasons, please read what Cheshire Figment wrote. Disneyland is a small park and it has a history of people abusing the GAC and disabled services. They want a GAC because they have blisters, it is too hot, too cold, whatever. The people who truly need disabled services and the GAC then were waiting longer because someone had blisters from cheap shoes or someone was looking for a short cut on lines.
Yes, there are people who truly need special services. The problem with the sun is that there is no place to wait in the shade in Fantasyland except in the earliest and latest part of the day. There was no shade at Small World, astro orbiter ride, Main Street Transportation, Mansion, canal boats, tea cups, etc. Pirates, Star Tours, Splash Mountain, and Roger Rabbit's Toon Spin however are indoor waits. Either you wait in the shade on Pirates or you are in the sun on the other rides. Some times there are shady areas near by to wait and some get shade during part of the day but Small World did not have any shade for 50 or more feet from the entrance unless you hunker down next to the gift shop area.
Could and should a person with severe sun sensitivity go to DLR. YES but go in the off season when lines are short. Take proof of your condition then talk to a supervisor at Guest Relations as you never know when they will change policies. You could also try to get the GAC based on your other disabilities. Study the youtube videos to see where and when is best times to go. Early morning and later in the day is when the shadow come out.
http://www.youtube.com/watch?v=ouP05nOMJ7s&feature=related
middle of the day
http://www.youtube.com/watch?v=p_pI8O21NcM
that one was done early in the morning based on the shadows.