The highlight size is too big and of the wrong spec shading type for the water drops, could use a blend node to change highlight size for just bump parts but think it really needs to be fresnel to get the correct effect and intensity.
To extract the spec from the diffuse map one thought is to convert it to bw using the HSV node and then use the step function from the math node to filter just the higher values which hopefully will be from the reflection/refraction highlights and either blend with the existing spec using the bump map as a mask or plug into the alt spec input.