[2019] A way to reward build creators

I would love to see a game mode/modes that would challenge players ability to farm and create different builds. Build creation is one if the games best selling points but, outside of pvp (which has it's own problems atm) there's no real reason to create different builds (or specific builds) other than doing it just for fun. Every enemy can be defeated (the fastest) with lmg's just as effectively as any other gun in any different situation in the game. 85% of the guns in the game (outside of lmg's,AR's and snipers) are underutilized or completely ignored because of this reason. If there was missions with modifiers or mechanic specifying a particular build with a particular gun type as (being) the most effective way to do damage to the enemys in said mission, it would add a new importance to mastering a build. One example could be a mission modifier that half of all enemy's armor are resistant to all weapon damage outside of rifles, pistols, shotguns and the other half is resistant to the same 3 weapons that does damage to the top half of enemy's armor (enemy's health is fair game). That's just one of many different game modes/ways to encourage and reward players build creation, one of the division's biggest strengths gameplay wise. I would love to hear if anyone else has any interesting modifiers that they would like to add to this idea and if they think this would be a cool feature to have in the game.