I'm in the camp that hopes for a revamp.
She's a very old hero who hasn't been changed much over time. However, I think one should be careful when approaching an overhaul because you don't necessarily want to change her so much that she's unrecognizable. Also, she is an introductory hero so you don't want to go giving her abilities tooltips like AA's ultimate.
Frost Arrows are a good place to start; they're an iconic aspect of her, since honestly right now orb walking is one of her few skills. Silence is powerful and would be nice to work in, but not sure if I'd consider it core to her playstyle. TSA and Marksmanship are utterly bland and could be removed with no harm to her enjoyment (as long as she still did enough damage).
With that in mind, I'd imagine something like:
Frost Arrows
Fire a freezing arrow at the target, slowing their movement speed by 30% for 2.5 seconds. If the target is hit by 3 consecutive Frost Arrows they are silenced and rooted in place for .75/1/1.25/1.5 seconds. 1 second cooldown.
-I imagine something like how the Shadow Demon and Batrider have numbers above their target's head, so you can see when they will be frozen.
-The cooldown is in place so that a late-game Drow can't simply perma-disable a target with a high attack speed.
Familiar
Summon a bird familiar to scout the area, giving you unobstructed vision of the surrounding area for 20 seconds. While your familiar is active your attacks cannot miss. 60/50/40/30 second cooldown. Gives 1200/1500/1800/2100 vision range.
-You do not control your familiar. It is merely a graphical representation that you can see the area.
-Allows the Drow to see past trees and up ramps, as well as negating dodge effects in a fashion similar to the MKB.
-This is not True Sight and does not pierce invisibility.
Trueshot (passive)
Gives the Drow Ranger an 11%/14%/17%/20% chance to fire two arrows when attacking.
-If the triggering attack was a Frost Arrow then the second arrow fired will also be a Frost Arrow. This is from both manually casting and auto-cast.
Markswoman (passive, Ultimate)
Increases the range of the Drow Ranger's attacks by 75/150/225. However, the damage dealt beyond 625 range is reduced. Passively adds 10/20/30 Agility.
-The damage reduction is calculated based on the locations of the Drow and her target when the projectile is fired, not on impact.
-Damage reduction scales smoothly from 90% and 25% between 625 range (her base) and her new max. This means she will be able to do more damage to targets as she levels up her ultimate.
With this version I'm trying to create a hero which fits the old theme reasonably well. She is still relatively simple, relying on orb walking and right-clicking for kills. Still isn't a major escape artist, instead relying on her superior knowledge of the surroundings and long range slowing capacity to prevent being ganked as easily. I tried to also make Trueshot more engaging/thematic as it interacts with the Frost Arrows to rapidly deliver an extra stack to the target (rather than simply being Critical Strike). And finally her familiar gives her an edge against certain heroes who rely on dodge to counteract physical damage.