I dont think the magnum is any slower than the shotgun. I dont like the shotgun so i dont use it much, but the magnum doesn't feel particularly slow compared to it. The shotgun is terrible, up close its a once shot kill (which is why many noobs like it) the big hit zone makes it easy to get a kill or two. If the enemy is more than 15 or so metres away, you dont do much damage at all. I think the shotgun up close is more powerful, (if your really really close) but its close. The magnum will kill the lower hp classes etc in one shot, a heavy i think goes down in 2. The magnum on the other hand is imo remarkably accurate if you crouch, its also has the advantage of being 100% effective at any range.
I mostly agree. When I spoke of firing rate in meant as a general comparison but not specifically to the shotgun itself. My frame of mind was more along the lines of how to survive against a magnum wielder. Chances are your weapon should have a larger hit box and a higher fire rate so the smart thing to do is to be as mobile as possible. With a shotgun just increase the distance between you and the attacker and you'll mostly win out just as you describe.
I won't complain about 100% accuracy across the map for the magnum or any gun because then I would be complaining about almost every FPS made with a MP mode...its not realistic to hit ANYTHING with an assult rifle from miles away especially moving targets. However, its a game so stuff like that is easy to excuse so long as I'm having fun.