And again:
Nobody here is talking about carrying two weapons simultaneosly. We are talking about the possibility of using a second weapon temporary.
This means: You are not able to carry two weapons. You can just grab a different weapin lying around:
-When you take it and switch your weapon, you automatically throw away the second weapon you have taken.
-When the magazine of the new weapon is empty, you automatically throw it away.
So, there is no possibillity of playing with a rifle and a SMG at the same time. You just uses a second weapon in an emergency situation. Imagine being a rifle soldier on an urban map. You are lucky and can kill an enemy SMG soldier when he runs into a hall. You also know that there are more of them coming to your position. So, what would you do in real life? Just crouch into a corner, hoping that the enemy will not see you when arriving? Just sit down behind the door to get killed after firing your first round on the attackers? Or would you just grab the PPSh of the dead soldier in front of you?
Well, I think I know what I would do.
Sadly, RO does not allow this ATM. Of course, you can throw away your weapon and take the new one - but in most cases, it just takes too much time.
So, a feature just to grab a weapon and use it until it's magazine is empty would be a nice touch.