It was the first World's for both skaters, and both have limited experience on any international event, especially at the Senior level.
Both made the mistakes of inexperience. Having the practice rink be Olympic size while the competition rink was a bit small even for a hockey rink can't have helped, either.
I thought the size of the rink was an odd thing. I don't know what other amenities and advantages London may have, as I have never visited. But it seems to me that the competition arena would be a major consideration when selecting the host for a WC. As I said, I've never been to London, but I wonder why they didn't use the Olympic rink for the actual competition.
Edit: I thought the size negated some power and speed advantages of some of the skaters, particularly the ice dancers. I thought both D/W and V/M got really close to the boards on occasion, and I would suspect they both had to throttle down the speed a little to adjust to the smaller rink. Does anyone know more about how skaters adjust to smaller facilities?