As someone who benefited from the GI Bill in the late 1960s and early 1970s, I saw how it allowed me to complete my education and find a new direction.
However, I would like to see such a idea modified slightly, to encourage service before receiving the benefits. That's how the GI Bill worked. I served a four-year enlistment in the USAF, after dropping out of college, which let me return to college afterwards.
A lot of people recommend a gap year for young people before beginning their higher education. It's not a bad idea. I had a four-year gap, during which I grew some in wisdom and was more ready to apply myself to my education.
So, perhaps a national service plan should include the opportunity to serve prior to further education, or in the middle of it. Many young people would benefit from time away from family and school before taking on post-secondary education. In many cases, they'd get a lot more from that education, if my experience is any example.