Lots of things can be trained in gamelike situations. Problem is to keep control of the learning situation.
You need to think about what you want to achieve, which particular element of the game you want to improve and work around that. In this "open" learning environment you will have the feeling that learning is slow, however, it has been proven that what is learned sticks better. The "closed" environment seems to bring faster results during the exercise but is farther away from actual game like situations.
What I do is "open" while keeping focused.
Example: line-out training - goal: support of jumpers. Try to neglect all the things that seem to go wrong with the throw. Make this a priority in another exercise.
Hope this helps....