Drow Ranger is an extremely powerful hero boasting one of the best passives and signature cards in the game. While her average stats are a definite downside, the sheer power level of a game-wide attack buff and a cheap lanewide silence more than make up it.
Drow Ranger has a very mediocre statline. 4 attack is the expected strength for a green hero, with only Rix having less. Her health pool of 7 is the lowest possible value for a green Hero, tied with Rix. Drows stats are a clear cut disadvantage to compensate for the strong passive and signature.
Adding one attack point to every other ally in all lanes is a very powerful effect. Even gaining as little as 5 attack across the board is nothing to scoff at.
Obviously, Precision Aura scales well with a wide board state. At the point when this adds 5 or more attack in a SINGLE LANE, you're getting absurd value from this.
Go ahead and track how much damage this contributes in one game. It's very easy to get 10, 20, and sometimes more. 'Is it meaningful damage' is another story.
If you ever have the choice, having Drow Ranger on the right lane is 'best', since the left and middle lane combat phase will benefit from her passive before she may potentially die in combat at the final lane.. While having absolute choice where to deploy Drow is a very niche situation, it's worth keeping in mind.
As strong as Precision Aura is, Gust is what cements Drow as a top tier hero. Gust is THE premium disruption spell.
After casting Gust, your opponents options for interaction are virtually zero. They may as well launch Hearthstone for that turn. Silencing all enemy heroes in a lane for FOUR MANA is a staggering effect.
As such, Drow Ranger is a natural fit in any combo type deck that wants to "go off" without fear of the opponent meddling in your plans. It isn't just for combo decks though. Locking your opponent out of tricks for a turn can break open many stalled boards no matter what type of deck you're playing.
Drow is powerful enough to fit into any deck packing Green, but you can further leverage her power with any deck that aims to go wide and abuse her passive or decks that can maximize the disruption caused by Gust.