The Commanding Office (CO) Koal in Advance Wars: Dual Strike is very young looking, but seems more mature than the other various Kid COs in the game (Andy, Colin, Jake, and Lash), excepting Sonja, who also acts mature. Even Max, the Dumb Muscle of the Orange Star COs, picks up on it, calling Koal a "small man". Then you remember that Kindle and Von Bolt drained the energy from Omega Land to keep themselves from aging. It seems very likely that this is why Koal looks like a child.
Von Bolt's Hannibal Lecture to Jake sounds selfdefeating and stupid to many players. But to Child Soldier Jake, who quite possibly has never had to really face the fact that his decisions lead to the life or death of his underlings and enemies, and certainly never on such a personal scale? Maybe Von Bolt was better than we give him credit for...
One of the main aspects of gameplay that changed from DS to Do R/DC was how the CO power system is almost completely reversed. In DS and the games before the main way to charge CO powers was to lose units, while the new system worked by fighting inside the CO zone and preserving your CO unit (your power progress is lost with the unit). This fits the Darker and Edgier story very well, placing importance on keeping units alive when so few people survived the apocalypse (as opposed to getting stronger by throwing units into the meat grinder) and the impact the CO can have when so much is at stake.