Every time Slark was viable in the professional scene, he was absolutely rampant in pubs. This generally happens to pub-stomping, snowball-oriented heroes and it is probably a nightmare to balance them, but for the first time in a while the pattern has been broken. Slark might not be the most popular hero in the professional scene, but he is situationally excellent and maybe it is time to give the hero a chance in pubs, despite his average win rate.
Over the last couple of patches Slark received a couple of very important laning stage buffs. His armor was increased by one, while his starting AS was increased by 20. This attack speed wouldn’t be particularly scary on any other hero, but Slark with his Essence Shift really benefits from it.
It doesn’t necessarily make him a lane dominator, but it allows the hero to play defensively through calculated aggression, much like Anti-Mage, Ursa and Monkey King sometimes trade their health for extra stacks of their ability or mana burn to prevent the enemy from being able to make plays.
Increased healing potential at level one of Shadow Dance also allows the hero to feel more comfortable in lane by the end of the laning stage, making hit-and-run plays even more effective. It also indirectly increases the farming speed of the hero.
The hero also received a couple of nerfs. Essence Shift stacks now expire after 100 seconds instead of 120 at level four of the ability, with lower level durations untouched. Pounce also doesn’t deal any damage, preventing earlier aggressive plays. Neither of these nerfs are particularly game-ruining for the hero.
Pounce level one used to deal 30 damage and most Slark players maxed out Dark Pact first. Losing 20 seconds on Essence Shift stacks is more of a macro nerf and while it does limit late-game options for the hero, it shouldn’t really have a huge impact on pubs.
The end result of these changes is a hero that is pretty risky and demands a decent lane, but can be absolutely devastating in the late game through one of the scariest midgame power spikes, given a good start. The hero can also hard-counter many popular mobility-based cores, such as Ember and Storm Spirit.
There are several new developments for the hero. They are probably quite playstyle-dependant and you can and should be flexible in your pubs, but these developments are definitely worth considering nonetheless.
Professional players now frequently get two levels into Essence Shift early on. Depending on the lane, it is accompanied by either Pounce or Dark Pact by level three, but these two Essence Shift points are more or less non-negotiable: the amount of deterrence you get from occasionally hitting the enemy hero is too good to pass on. 2-1-2 by level five is the most popular skill build for the hero, with Dark Pact maxed out first.
Secondly, Hand of Midas is now a thing on the hero. Given the state of the meta, it does make a lot of sense and Slark is one of the heroes who gets real benefits from extra attack speed, but this item choice also means the hero can no longer be played as a tempo-carry.
No matter how well you play or how good attack speed on the hero is, Hand of Midas is still a tempo hit. Almost similarly priced Shadow Blade and Echo Sabre do more for the hero in terms of damage output, survivability and ganking potential. And both of these items allow the hero to start fighting or looking for kills, but only if built early enough.
If your team does need a tempo-core, Drum of Endurance also became a very popular option. It gives great stats and, perhaps equally importantly, extra movement speed, which allows Slark to stay on his targets and be a threat even without Shadow Blade.
In fact, Shadow Blade is no longer considered a mandatory item for Slark and many players now go for Diffusal Blade into early BKB instead. Diffusal Blade is one of the most cost-efficient DPS items for agility carries and it really shines on Slark, especially in games against heroes with an already limited mana pool—by both decreasing the intelligence of the enemy and burning their mana, leaving the enemy out of options can be accomplished in a matter of several hits.
Talent-wise, most professionals agree on +10 Strength at level 10, since the hero doesn’t really need extra +6 Agility. They also generally go for lifesteal over attack speed at level 15, since, once again, they are attempting to cover weaker sides of the hero, instead of double-downing on his strengths. Following similar logic, they take extra leash duration over extra dark pact damage at level 20 and to allow Slark to have better macro options in the later stages of the game, they usually go for extra Essence Shift duration.
Current meta is wide open, doubly so in pubs. Finding ways to get an advantage over your opponent was always a crucial part of the game, but right now, with so many viable heroes, flexibility is probably the most important attribute for being successful in pubs.
Stay calm, stay smart, train different heroes and play as a team and you will surely prevail.