Absolutely agree to this! The whole 2 gun thing is really frustrating. Yes yes realism, "noone could carry all that" FFS, I'm a supersoldier in a nanosuit shooting aliens and giant robots, it doesn't get more fictional! If I wanted realism, I'd play "Waiting for 20 minutes at the bus stop" or "My reception is really bad, let me more near the window".
How much more fun would Bulletstorm have been had we the ability to switch to different weapoons on the battlefield? It is fun to go between long, med and short range action with the cool tools of the trade. We have the 10 number keys, put them back to their intended purpose and two weapon limit be damned!
Saying that, I kinda liked Dead Space 1/2's way of doing things. 4 guns at least gives more tactical options, as well as the ability to have a favourite and not totally gimp yourself if it's not necessarily the best weapon. Resident Evil 4 style was also an interesting one (Chicago Typewriter, Broken Butterfly and Infinite Launcher barely fit!).
The only time I suppose it's excusable is in a Rainbow 6/L4D2 style coop/squad based shooter where everyone has a specific role, or where it's the overall team loadout, cooperation and skill that makes the challenge. But in non squad based or coop MP FPS, NO!
Our devs, hallowed be thy guns. Give us back our daily shotguns and assault rifles, return to us our dual pistols, our sniper and our rocket launcher. Forgive us our flak cannons as we instagib those who use their miniguns against us and lead us not into cover-based and regenerating health temptation. Amen.