Well it would still eat up an option and put the player on the 40 man, so I'm not sure it would be much different than it is now. In fact, I suspect it would help most players stay up longer rather than the other way around. I have doubts a team would keep a guy on the 40 man specifically to play him 14 days a year for a few years.
I think it's the solution that would result in the least amount of manipulation by teams, but I'm sure there's probably one or two guys who would end up worse off. In any kind of change, there always are.