Disclaimer : I am NOT a racer. This is a good time for me, a better player can definitely get this under 1:20, probably even faster. Getting even remotely close to my witch/templar arma/crema times on a shadow is awesome.
tl;dr : Shadow levelling is painful. Blade Trap solves that by doing unreasonable amounts of damage very early on (especially on stationary act bosses) and allows use of Whirling Blades without weapon swapping. This gets us to act 4 and lab done which is where most trap or mine builds will pop off on a 4-link.
The Shadow has a really rough levelling start compared to the Templar and the Witch, not having fast and efficient access to the free damage from the fire mastery and/or the dual wield mastery, and having a whopping 0 resistance nodes to take. This makes the usual Rolling magma/Flame wall into Arma/Crema setup much less powerful, not to mention the Shadow doesn't get Holy Flame Totem. The gear pressure is thus much higher on Shadow. (I help Alira on launch)
This setup solves early damage at a point where clear speed is much less important, while utilizing the mobility tool the Shadow gets, which is Whirling Blades, right from level 12. Melee weapons with flat elemental damage are much more common than Rune Daggers with flat added to spells early on. In a fresh SSF start environment, this is much stronger and faster than other Trap skills. This allows us to move fast, and kill blue packs and bosses quickly.
We spec into trap nodes and life, so a transition into any spell-based trap is painless after we unlock the flat fire damage recipe in act 3. It can also easily respec into mines, needing only 4 respec points to remove the Expeditious Munitions wheel, and pathing up towards Efficient Explosives instead of down towards Unstable Munitions.
I'm not convinced about how I did act one, maybe Stormblast mines or Frost blades is better. Feel free to tinker with auras, I used Haste for speed but Grace is probably better. Also, there might be a case for swapping to Shield Charge or Leap Slam after doing the Library (which we do for Charged Traps anyway), especially if pivoting off of Blade Trap.
Shoutout to cdrpoe's filter :
tinyurl.com/bd...
I used the Blade Trap one.
Pob
pobb.in/tWud_n...
www.twitch.tv/faeder