That's not a bad idea, after all it is what's used for iPhones and iPads, but Macs have much higher power requirements and then it has to be implemented using a MagSafe design.
People also manage to break their USB - Lightning cables the same way too, of course they are only about $20 to replace.
Personally I think it's a solution in search of a problem, since I have yet to experience a single problems with any of my portable Mac's power cords, even the barrel style that predated the MagSafe design. They're well over ten years old now. Same goes for the iPhone power cords, and even the original iPod cables, all still perfectly fine.
Other people go through several a year. The problem isn't with the cord.
I suggest you make your suggestion to Apple: http://www.apple.com/feedback/