You have 3 wires going from each motor to each ESC, and you have all of the power wires and servo cables. How much does all that weigh?
As I expand the database I'll have more information in this section about wiring sizes and how you can save weight. Its important to choose the right size wire for each application. The wire needs to be big enough to handle the power (amps) going though it. If it isn't, it can get hot and melt.
On the other hand, if you use wire that's too big, you're just adding extra weight with no gain.