Originally Posted by
Maelstrom51
I'll point out some pros with Sub since the conversation seems mostly focused on Assassination and Outlaw.
AoE is better than you would expect. Between Relentless Strikes and Master of Shadows you never run out of energy, allowing you to spam Shuriken Storm and Nightblade. Nightblade has DPS similar to Rupture, but it doesn't last as long. You are also constantly in Shadowdance, so the Shuriken Storms actually do some damage.
Sub also has a niche that I'm not sure any other spec has - dramatically increased single target while multiple enemies are present. By spamming Shuriken Storm -> Eviscerate you can burst down priority targets extremely quickly.
Sub's single target is plain superior to Outlaw, and is close to Assassination's, but in lower mythics it won't shine because Assassination's burst is so much higher.
If you get the legendary boots or legendary cloak Sub becomes amazing. The cloak lets you compete with mages and such on AoE, while the boots make you one of the strongest single target specs in the game.