English rod makers already use a similar method called the "test curve". They hold the rod parallel to the ground and tie a weight to the tip. If the weight pulls the tip of the rod perpendicular to the floor, that is the "test curve" of the rod. A light rod has a test curve of a few ounces whereas a heavy carp or pike rod will have a 3 or 4 pound test curve. The test curve of the typical crappie rod would measure in ounces.
As you say, I think many rods are damaged before you buy them. The blanks are thin, and they're being shipped from China, so some are bound to be damaged during the shipping process.