Can we get a buff to Last Whisperer?

Last Whisperer and its builds feel like crap. Recently, i played as ezreal. I got last whisperer and we were doing fine, in a winning position. My team throws in a single teamfight and the enemy team suddenly gets tankier and i dont seem to make a dent. The same thing happened again last game. I went Lucian and early to mid game, my damage was fine, but late game once again i did no damage. The enemy vayne meanwhile melted our volibear as if he had no defensive items at all. Should i buy duskblade of drakthar for these situations? Or does last whisperer need a buff? Or should i not even be playing Lucian? (Lucian has kinda low range too, making it dangerous for him to deal damage in a teamfight).