FEAR did it right, with the akimbo pistols. So did Max Payne.
If a game's going to include dual-wielding, then at its core, said game should focus on style over realism.
There's a reason soldiers aren't issued with two sidearms. Your aim suffers, it's harder to reload, you'll fatigue faster because you're not supporting the weight of the gun properly, and at the end of the day, if you want the better rate of fire, why not just use an SMG?
Dual-wielding with firearms is
stylish not practical.
With melee weapons, the same is (loosely) true, although there are a number of martial disciplines which emphasise it. Kamas are generally used in pairs, for example. For the most part, though, melee weapons that are designed to be dual-wielded come in recommended configurations, one smaller than the other. The Samurai carried two swords - one long, one short - for that reason. Similarly, Western duelling and fencing styles have a number of specialist weapons, such as the "Main Gauche", that were designed to be wielded in the user's off-hand, opposite a longer blade.
Desert eagles - why would they be retarded? I mean yes the kickback would wreck most people but soldiers can fire them one handed, and if you wanted to look awesome 2 of these is how to do it
If not handled carefully, the recoil on a .50AE can easily break the wrist of even an experienced shooter, and just being strong won't be enough to stop it happening. Desert Eagles are designed to be fired from a braced two-handed stance, and ideally you should keep your arms slightly loose so that the gun's kick raises it above your head, diverting all that energy so that it doesn't hurt you.
Anyone who tries firing one single-handed is just asking for an injury. An injured soldier is a liability. Rumour has it, in fact, that in SAS training they kick your arse for jumping over low obstacles, because if you twist your ankle on landing, then you're going to be slowing the team down and endangering the mission.
Dual desert eagles = double the risk of breaking your wrist = BIG no-no.