I think wiremod has really expanded what could be done in Gmod, at least it did for me. I never wold have been able to build giant pinball or pong without it.
While I agree that endless copies of engines and turrets are boring, I definitely think that wire can be a huge asset given a little creativity.
(Plus, when you're running Gmod on a laptop like me, you don't have a numpad, so some other form of input is a must. Thank god for the pod controller.)