Subclass mastery with destiny 2 (assuming that you guys let us keep our guardians). My plan for it goes like this: in each Subclass you have the skill columns; grenades, super, melee, passives, etc... What I propose is that, at the cost of 5(ish) exotic shards, we be granted the ability to choose one of the skill sets for each column and be able to build our own super class from abilities that we already have. But, you can only pick one, with the exception of grenades, because you can only equip a single type anyway. Make it so once you build your new subclass, you have to use shards to change it if you realize you don't like it. That way, bungie will keep us farming for shards, and we can follow up a smoke grenade with a tripmine. So something like a bladedancer with shadestep and tripmines, or a defender with thermite grenades.