Lucian was always a good adc but never the best.He got several nerfs,his enemys got buffed,etc
Now when the essence reaver got buffed it makes alot stronger.Lucian was always the ad caster
and the the marksman.in the early to mid game he has a lot of burst due to his q and ult
now where to ult got buffed for the early game its alot easier to get ahead.His passive is extremly strong for lategame.Both can crit makes his crit dmg to 300% crit dmg(375% with ie).

+ good at all game of the stages - low range
cause of his kit - e doesnt remove slows anymore
+ burst and sustained - q can be dodged
wow
+ low cooldowns
+ good duelist and teamfighter

Lucian is always for kill lane not for farm lane.So poke with ur q and go in after ur support engage