Seems unnecessary to me. The 'shared cooldown' never lasted the full duration of torpedo reloads for me. In other words, I could fire one, wait a couple seconds, and fire the other before the first torpedo launcher reloaded. I just couldn't fire them both at the exact same time. This could just be because I was mixing Quantums and Photons, but you get the idea.
Also, doesn't really seem necessary because one torpedo launcher per facing is plenty if you get a tactical officer with torpedo skills. Use the other facings for beam arrays, cannons, etc.
It ties into how shield facings work. They don't want you firing off a huge burst of damage, then turning away, firing off another one, then turning away. If torps had short range, like cannons, they might have allowed volley fire, but as it is they're very powerful weapons that require no power to use while being able to hit at maximum range.