currently its not worth heating arty as a lot of the time the reduction in cycle time barley raises the paper DPS and is often so little that with server ticks the actual dps increase is even less.
now this could be done by simply adding heat to the damage multiplier rather than the cycle time but this would take some good 'ol balancing work as too much could cause major problems with alpha increase (I believe this is one of the reasons it is not done this way)
or my personnel favorite is to have it added to tracking speed this would be less problematic than the damage multiplier but more useful than the cycle time. It would also be an interesting dynamic where you heat a weapon not simply for raw dps increase but to try to apply just a little more dps to that ship sig tanking you