I think this is going to make choosing alliance partners particularly complicated- if you take bonus points into consideration, you've got to think about which robots are easy to lift, which can easily lift others, etc, etc.
Plus, think of all the design choices. You can have a hook for another robot to lift you, a hook to lift another robot, a ramp for another robot to drive onto, be small enough to drive onto another robot, a combination of the above...
I know, I know, the real game is about the game pieces (and usually decided that way), but I've always been a sucker for the bonus points. =)