*sigh* i think it was mentioned at some point that all hand seals do is help u gather chakra to certain places (during the neji fight we learn that even for jounins, gathering and using chakra is difficult, and the hands and feet are the easiest place to gather)......so the number of hand seals are related to the amount of chakra needed to perform a jutsu.......as u grow stronger, u learn to control chakra better (as well as gain more chakra) so the same jutsu would b easier to do (ie: bayakugan)