From my experience as an international WLM organizer, indeed what's lacking is a user who is aware of all the details and at the same time can be available most of the time to answer questions and communicate. This is very difficult: usually you have someone who is either available all the time, or is aware of all the details.
However, I also found a problem that I don't know how to solve, and as I understand it was present in all previous years: that in some countries the team is very small/busy and it's very hard to get feedback from many national teams. As far as I can tell, some national teams don't have anyone who follows this (general WLM) mailing list.
One other thing that posed a problem this year is that the team was set up so quickly that it wasn't clear to everyone whom to talk to about what. This is where we actually need (as Maarten said) a dedicated core team, and too many people will be counterproductive. Even with this year's 3-person international team we had a few internal communication problems, so I can't imagine how it will work with a huge team (say, 10 people). Dividing the tasks among a few people is easier than among many people.
Finally, another major point: ever since Maarten left, we haven't really had a technical coordinator (talking about managing the tools, not the campaigns which was done quite well by Romaine). True, last year Platonides handled it and this year I did, but there's a very steep learning curve and the "job" was pretty much imposed simply because no one else wants to do it—so many people were disappointed in the last 2 years. Therefore the most difficult position to fill by far (IMO) is that of technical coordinator who has both enough time and knowledge to handle the project.
—Yan (Ynhockey).