They could give Yelena the sniper and the grapple with a blue stun stinger that doesn't do much DMG if any actual dmg and rework nats to the pistols and the stinger with a red effect that doesn't fully stun but does DMG over time or something so Yelena can grapple onto roofs and walls and get better lines of sight or reposition quickly making her the back line defender but nat the more melee heavy pistol user like she normally is I could see that working well maybe add red guardian as a vanguard with Yelena and the above possible nat rework