All of the heroes below were extensively reworked during 6.86. These are the new abilities and functions you'll see during competitive matches now that 6.86b has dropped.
A Refresher on 6.86
Doom no longer posesses Level Death. The hero has traded his personal linkens-popping nuke for Infernal Blade, an autoattack modifier that allows him to burn 1.25/2.5/3.75/5% HP on hit. This change has made him a stronger laner, but greatly increased the effectivity of Linken's Sphere against him.
Faceless Void lost his most famous RNG ability. Backtrack has been removed an in its place he can now use Time Dilation. With this spell Void can freeze the cooldowns on all enemy heroes in a 725 AOE for 5.5/7/8.5/10 seconds. It also applies a percentage-based attack and movement slow to heroes that are hit. Additionally Time Walk has been changed to work as a "mini timelapse", allowing Void to jump away from danger and undo any damage taken in the previous two seconds.
Death Prophet is no longer dependant on Witchcraft for her scaling. The scaling of Witchcraft has been added to her other spells, while the slot in her ability bar is now taken by Spirit Siphon. It is very similar to Pugna's Life Drain with an added slow.
Lone Druid and his bear can now both activate a new ability called Savage Roar, which causes enemies in a 325 AOE to run towards their fountain for up to 2.4 seconds. Synergy has been removed from the hero, and all Synergy scaling has been transferred to his other abilities.
Winter Wyvern has had her ultimate completely reworked. Winter's Curse now makes all affected units invulnerable to damage from enemies. Instead, it now lasts longer and grants extra attack speed to the heroes attacking their own teammate. This means that the spell loses most of its functionality as a disable and becomes even more of a disrupting teamfight ult than before.
6.86b Changes
Rikimaru has still not been re-enabled in Captain's Mode. The notorious backstabber did receive several buffs, however. Arcane Rune's mana cost reduction has been nerfed, Outworld Devourer received buffs to Arcane Orb and Astral Imprisonment, and Meat Hook's Aghanims Scepter damage has been nerfed.
You can find the full patchnotes here.
Reactions from the Competitive Scene
Not everyone was happy with the swift return of the reworked heroes. Several teams were scheduled to play the MarsTV Dota 2 League qualifier finals this evening, and they suddenly had a handful of new and unpredictable picks to work with.
Sources: Dota 2 Blog
