Now, this requires some explanation... but it's purely a concept-based idea. I personally have been hoping for a manipulator-important multiplier/bonus for awhile. Some teams designed very interesting manipulators for the tetras, but it wasn't necessary. The concept below is based as an idea that could be used for a multiplier/bonus thing and/or a last-second finale (providing incentive for teams to have tall reaching manipulators that can also modify the scoring object). The main thing I would like to see though is a scoring object that can be manipulated in some form, where it can make a certain number of points without manipulation (to provide a simpler task for teams) or more points to create a manipulator to perform the higher-point task.
This example shows a square that has a hinge in the middle of it's top start. Teams would have to grab the object from a stand (similar to tetras) from the side of the field and then place them like those child-block toys into a goal hole on the wall. They can place it into the lower, non-manipulated hole for a lower bonus score or the higher goal in which the object must be pressed in to form a triangle to fit into the hole. Once you fill the hole though, you obviously can't put another one in. Thus, if a team is good at this they could technically fill both holes on their post for the low and high points. Retroreflective tape could assist robots in lining up the objects encouraging an automated method to do it. As for the material of the object, a number of things could be used, and I don't think it would be any harder for a team to assemble than a tetra.
Note: I wasn't sure which thread to put this in (sensors or scoring objects) because I think this would highly encourage sensors as well. I know this idea is pretty complex, but I'd love to see manipulated objects and this is just one idea to throw in the massive hat that becomes the GDC idea hat. Good luck GDC, can't wait to see what we get next year.