I think it is a very commonly held belief that the Half Marathon course during WDW Marathon Weekend is the worst rD course. It is certainly my belief. This year may have been my worst experience with it yet.
Coming out of the last corral (I can't complain about the placement, it is what I earned and where I belonged) was very unsatisfying. We started over an hour after the first wave and I found myself running in the grass during most of my intervals; I think the lack of sure footing was a contributing factor to my blister issue that caused me to miss the Full. The sheer volume of runners was an issue throughout most of the course for me.
The course itself is a mail-in as far as I'm concerned. MK is cool and all, but when it's the only park on the course (does that tiny sliver of Epcot actually count?) it's pretty disappointing. I think the size of the race plays a big role in their inability to get more creative with the course. They seem to focus on getting onto the widest roads available and it still feels very compact in a lot of places.
The Half at Marathon Weekend was my first race ever in 2012. At the time, I thought it was awesome. Time and other races has severely changed that opinion for me. I still prefer a mile or two of MK to most local races (cities are cities, buildings are buildings, roads are roads
) and, I guess, I understand why the course exists as it does; but it's still a disappointment and the least fun of the four Dopey races.