Even though you can play the game any way you want to class exotic items show how bungie intended the classes to be played, at least by weapon type. For example hunters class exclusive weapons are a handcannon and a sniper rifle. From day 1 bungie has always said that hunters use precision damage to accomplish their goals. And when it comes to hand cannons and snipers if you're not getting precision kills then you're wasting your time. Warlocks have always been linked to fusion, pulse rifles and Titans to auto rifles and shotguns. Plus you can get some really good synergy with those weapons and the right perks active in your skill tree.