Surely, not through known severe weather! When I recently flew ATL-TPA we were informed by the F/D prior to departure that we would take a weather avoidance route which would (and did) add about 10 mins to the normal flight time. This on what is generally a short 1 hour flight!
I said CLOSE to most cost effective routings, no implications of taking it through severe weather... and even if operations planned it, the authority lies with the captain/crew to accept the routing or not!