As having served 19-1/2 years military, full and part-time, and in places where I got shot at on occasion, I've no problem with national service being a requirement.
I'd have a whole lot of ways you would qualify for it: School teacher = time served. Volunteer or full time fireman or paramedic = good to go. Work at the local animal shelter = okay, next. Police officers = done. Same for doctors and medical techs. Fire forest fires for a season or two. Volunteer at a youth center. Drive for the elderly or deliver them meals. Lot's of possibilities.
Basically anything that comes under the realm of public services, emergency response, or volunteer activities would count toward time served in performing national service. Pick up trash along the road on weekends. Clean up a dump site. Lot's of ways you could get "credit" or "exemption" from service.
Want to buy your way out of it rich kids? Sure... mail the check here, and no, it's NOT tax deductible!
We don't need national service? Maybe not, but I think the nation as a whole could benefit GREATLY from national service, and certainly many of the young adults could benefit from such activities, even if forced to do so. Sense of community? A sense of pride in accomplishment?
Flip side, there would have to be a lot of oversight for many of these activities and a screening process. No good deed goes unpunished.
And to any of you about to cry about "YOUR FREEDOM"..... I'll remind you that your freedom did not come free. It's paid for in blood and sacrifice. Doing some volunteer service seems a pretty cheap price.
People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. --- George Orwell
Time for the rest to pitch in.