While I don't like the thought of mandatory 2 year NS being made a legal requirement, there is a possibility that something needs to be done given the precarious state of the world at the moment. A million or so 'reserve' troops who are trained would act as a deterrent if nothing else. If something kicks off in 10 years time it's not like we didn't see the warning signs coming so doing nothing and hoping it doesn't isn't a real option.
I would like it to be shorter, perhaps take in vocational education at the same time, lose the hand to hand/knife combat and kill or be killed mentality training elements, as we don't want to have thousands of young men who can take people apart in a pub fight.
At the end of it they would have the ability to take apart and fire guns, work tanks and other heavy machinery, with maintenance and servicing knowledge, fly drones and so on. They'd come out with a vocation certificate, hopefully an understanding of the importance of exercise, good diet and discipline. If they could handsomely paid (for a teenager) for a positive experience that someone would actually like to do then it could be beneficial to all. If called up (hopefully volunteered) they could have the refresher and combat training and they would be ready to go in the fastest possible time frame.
The issue is they probably won't do any of that so it will just be standard recruit training and I'm not up for that. As with any idea it's all in the detail and execution.