I agree with BD.
Some years ago I worked at a unit whose radar showed precipitation. One pilot asked if I could vector him clear of weather, and I gave him a nice clear course between two cells. 'Thanks' he said afterwards. 'that was the roughest bl**dy ride I've had in years.'
A few months later another guy asked if he could deviate due weather, and promptly flew through the heaviest clutter on my screen.
So it's no use relying on the clutter that shows up on the shorter-wavelength ATC primary radars. If ATC are going to have radar to show 'weather', it has got to be to the same spec as aircraft weather radar.