There is nothing wrong with that type of roof. I think it is cool looking too. As long as the structure can support the weight of snow you will be fine. Most of the weight is going to be in the center valley. One very important detail is to make sure that the valley metal rides up both sides of the roof high enough to allow for snow build up without any water protrution. You also must have sufficient pitch in the valley itself to drain the water out into a leader head, gutter, or drain which ever may be your case. Eighty percent of the time in my experience especially flat roofs are never pitched to the drains properly or enough from day one.