Noise 1D doesn’t need a W input, they could have just taken the X coordinate of the Vector input. This would have been consistent with the 2D version that uses the X- and Y coordinates of the Vector input.
The 4D does need an extra input, because the Vector in Blender is only a 3D vector. The letters X, Y and Z were already taken, so they used W, being closest to X, Y and Z in the alphabet. They could have used any letter (maybe A, because it comes ‘after’ Z when wrapping the alphabet around..), but by staying in the same ‘area’ it is more clear that this is also a ‘coordinate’/ has the same function.
I’ll come back to the second question after I’ve watched the trailer 😉
