@g_F :envy
With further regard to the "wet runway" argument for NWS off...
This is the wording of FAR 25.149(e) as introduced in amdt 25-42, in 1978:
(e) VMCG , the minimum control speed on the ground, is the calibrated airspeed during the takeoff run, at which, when the critical engine is suddenly made inoperative, it is possible to recover control of the airplane with the use of primary aerodynamic controls alone (without the use of nose-wheel steering) to enable the takeoff to be safely continued using normal piloting skill and rudder control forces not exceeding 150 pounds.
Yet in 1978 there was no consideration for wet runways in Part 25 - wet runway performance was only specified in Part 25 at Amdt 25-92, in 1998. If one were concerned enough about wet runway effects on Vmcg, surely you'd ALSO impose wet requirements for braking, for example. The reality is that there's no logical link between the NWS requirement and the state of the runway.