Like I said before, the DOD needs to figure out how much it spends on the 20 year retirements. They then take that money and apply it to TSP matching. If Lt/Amn Snuffy wants to be responsible and invest his cash, he gets a little reward. If he wants to buy the 2012 Lexus/BMW/Monster Truck with the cash, he doesn't get Uncle Sam's contribution.
I think this would be the better system overall as it would provide retirement benefits, it puts the money into the free market a little more, and it promotes fiscal responsiblity. The best part to the government is that if General Ilovemytoys, spends all his cash on hookers and blow, they are out absolutely nothing after his 20+ years. Additionally, how much money is an Amn really going to stash in his first 5ish years? They aren't going to lose anything by offering this to first term airmen.
On another note, I'd me more than willing to have them reduce my salary from $80k/yr to $70k/year if they could get rid of queep or hire more people dedicated to doing the queep jobs.