Is Lawrie really missing significant development time? I know exactly what you mean, young players need to play, and play lots, in order to improve while they still can. However, in the case of an uber talented 23yo, whose biggest flaws are on the mental side of the game, is playing time as important as the mental lumps Lawrie has taken over the last couple seasons?
You don't have to be a scout to see Lawrie is an excellent defender and already posses the elite raw bat speed and power needed to be a successful hitter in the MLB. His approach is way off and he has too much movement in his swing but that can/should be improved over time as no one has ever doubted Lawrie's work ethic. He needs to learn how to take care of his body, to stay consistent, to stay unemotional on the field and to be professional. Those issues (among others, like throwing equipment at umps) point an immature ball player and to a mental side of the game that requires a lot of growth in order for Lawrie to reach his full potential.
IMO the struggles over the last year and a half will strengthen Lawrie and make him a better going forward. Obviously, Lawrie needs to make some adjustments when he gets back. The results haven't been there and pro-ball is all about results and making the right adjustments. We have all witnessed that Lawrie has the raw ability and athleticism to be a force on both sides of the ball. However, the question still remains; does Lawrie have the mental fortitude to make adjustments, stay healthy, get through slumps and maximize his results?