its great that you will get a new one! Have seen it quite often that people run around with rimowa luggages broken on a corner. the thing with Polycarbonate is that while being very resistant to impacts, it does not have a high elongation at break. meaning if the elongation of the part gets too high under an impact, it will crack.
OH and by the way: The way some guys handle the luggage, there is no way anyone could make one that never fails, unless they double the weight.