How I think every agent could be nerfed if Riot wanted to. I'll try to keep it balanced. This is just for fun and not serious suggestions.
Jett: smoke takes like 0.5s longer to bloom
Neon: strafe speed reduced, stun lasts shorter
Raze: reduced damage from first nade explosion
Yoru: lower duration on both flash effects
Sova: reduced duration of drone ping
Gekko: 10s longer cooldown on the lil pals
Kay/o: wind-up of flashes is louder
Omen: paranoia travels slower, smoke duration reduced by 2s
Cypher: trip gives a single-point ping rather than a constant scan, cam pings twice instead of indefinitely until removed, 7 point ult
KJ: max distance at which turret can detect enemies reduced
tbh nobody else would get nerfed
think the kitchen was left smoldering with this one