All the ranged rogue souls have their own unique mechanics. There are very few skills in one ranged rogue soul would help those in another, mostly only in the tier 1 branch.
As a result, almost all soul combination for ranged rogues use melee rogue souls for their sub souls. Assassin is one of the popular one. Unfortunately, the current design for Assassin Soul Tree is forcing you to waste 3 completely useless points for ranged rogue in tier 2. Any chance that you will swap the tier-2 Cloak and Dagger with the tier 3 Silent Footsteps? After all, if you are going to take Cloak and Dagger, I am pretty sure that you intend to spend more points in the Assassin tree so moving it to tier-3 won't be a problem. BTW I have to run to GSB and RoS every week and stealthing with 30% movement speed up would make it less frustrating.