Black Sabbath recorded some songs in regular E tuning and certainly didn't have pick-ups that were 'hot' or anything like the pick-ups that are classified as 'metal' pick-ups. I bet they weren't all that dissimilar to the 59/09's. I don't like 'hot' pick-ups but I haven't struggled getting a metal sound and I bet of you gave the guitar to someone like Ola Englund, he would get a metal sound from it - I can get a metal tone from 58/15 LT's (and I am not the only one) so I don't believe the 59/09's can't do metal!!
Do you have other guitars that give the sound you want? What gear are you plugging into? Have you considered a new Pedal or trying different settings on your pedals/amps, different amp channels etc? Of course they aren't going to sound like EMG's and not push an amp as hard - but you can use a higher gain Amp/Pedal, change the settings etc to get a great metal tone...
Tone is subjective I know but I doubt any PRS Pick-up wouldn't be able to do 'metal' in general but to fit your specific taste with whatever gear and settings you have, they may not work for you. That doesn't mean they can't do metal though and metal is a very broad genre too...