I was thinking about the whole engineers and legendaries issue and thought of something fun. A kit that “modified” the weapon you were wielding. e.g. Have a rifle mod kit that turns our shotgun into more of a sniper rifle. You equip the kit and it replaces your 1-5 with new skills. You get the keep the appearance of your current rifle, but add a scope/effect, so that you can see it’s the rifle kit.
For the pistol, I was thinking something like a silencer to make it more of an assassin style weapon.
Engineers are tinkerers, let us tinker with our own weapons.
Anyway, let me know if you think this would work.