An eye for an eye just leads to a lot off very short sighted people
The punishment needs to reflect where the child is at. For a first offense, at 12, given the circumstances of his arrest, detention and court hearing, the punishment sounds approriate to me. He needs to know he can never do it again. Most kids would be scared rigid by the experience and that would be it. The programme is to get him to understand why he did it and to better equip him to resist peer pressure in future. This bit is not a punishment, it's about preventing re-offending.
If a child sees this as getting off light and does it again, then the punishment has to be increased to have a deterrent effect. There's a real risk if you do this straight off that the child who has already learned their lesson will opt out, think of themselves as the criminal they are being treated as, rather than the reposnisble person everyone believes they can be and (worst of all) continue to mix in the company of peers who will lead them astray.
I've visited young offenders centres, Merika. You would not want your son there. There's a very high proportion of mentally ill. Self harm and attempted suicide are common. The prison officers I've met feel they are just holding back the tide. They exclude from society but there is minimal rehabilitation and a very high rate of re-offending on release.