I wouldn't want to switch with anyone. I'm lucky to have a condition that is treatable, manageable, and not fatal. I can still live my life while dealing with diabetes - I just have to work a little bit harder at some things. I'd really rather have no chronic condition. That being said, I suppose a thyroid condition (hypo or hyper) (preferably the one that makes you skinnier) wouldn't be too hard - there's treatment and not too much to deal with as far as I know.
But if I could switch chronic conditions, I would want the Alexandria Genesis. (Well, it's a syndrome, but I think that still counts?) I mean, purple eyes, dark brown hair (which I already have and love), no sunburns, no periods (!), long life, no body hair except for eyebrows and perfect vision, and never overweight? Who WOULDN'T want that? Unfortunately, it's a very rare condition and it may not even exist. But it would be great, no?
My participation in the DOC has affected how I treat people with other medical conditions. I feel like I understand a bit what they're going through - I'm more empathetic, more willing to listen, more able to help them out. Those of us that have chronic conditions - be they the same or not - know what it's like to deal with stuff. We all have a connection, and we can all empathize with each other. So yes, because I talk to/read about other people with diabetes, it helps me to understand other conditions. :)