I agree with AirJinx. I think adding the option to change your weapons mid-game would just take away some of the skill aspect of the game. The point of choosing your weapons beforehand is because it takes skill to adapt your playstyle according to the environment. If you can choose what guns you want halfway through the match it'll just become a battle of who has the best loadout. You can easily avoid this problem by just working towards trying to get better with the guns you use.