Hanzo’s projectile speed buff made him feel less unique, while increasing his projectile speed did make him more viable, it took away from Hanzo’s unique skill-curve. It made hitting shots not just easier at far ranges but easier to land at every range, simply put it just made him easier to play.
Hanzo is a high-tech sniper, so what if his arrows increased in speed during flight?
This means that you could decrease Hanzo’s projectile speed by half which would be closer to Hanzo’s original projectile speed, before the 2x speed buffs he has received in the past and make it so the projectile speed increases by something like 33% every 10m of flight.
This would mean that anything below 30m of range, Hanzo’s projectile speed would be significantly slower but at long/very long ranges his arrows would be much faster. At long ranges it should equate to roughly similar projectile travel time as we have currently, yes the arrows would become quicker than they are currently at beyond 30m but because they were travelling slower at below 30m, they should arrive at their target at a similar time without this change.
Basically this change would mean that at 30m or below Hanzo would play a lot more like old Hanzo, with more leading and prediction. At long ranges, he should play similar to what he does currently, maybe slightly more consistent but depends on range.