I wonder if this co-op mode would be better suited to teams within the same gym. Maybe it would work better without any teams at all? Individual competition through leaderboards could be interesting. The motivational factor, especially for new people could really be useful as well. I know a lot of people are saying that it is not in the best interest of the gym - but which gym would you rather sign up for? As soon as one big gym does it the others would have to follow just to keep up if it does well.
The co-op mode is still pretty interesting too though. It could lead to better camaraderie and feeling of belonging amongst gym goers. Any time you can get a group working towards a common goal I think you can accomplish some interesting things. I really like this idea and hope to be able to be a part of it someday.