My most successful Rogue build thus far has been a pure Scoundrel rogue as far as skills, but by dumping all of my Skill Points into Dual Wield, as it provides the best return on damage investment.
Maybe one point in Huntsmen to have access to Tactical Retreat. Any other enhancement skills are better placed on another character, such as a supportive mage.
I do believe that Elf is by far the strongest Rogue option due to their racial skill and innate Finesse. Also, the self healing from body parts allows them to sustain after escaping a foe.
Pumping Finesse to max and then extra in Wits worked well for me, but you might want to find some items with +Initiative to really get a good start to your turn to assassinate the key non-armor target to start benefit from Warlord.
The most important traits are in this order:
Backstabber
Warlord
Pawn
At that point it gets a bit iffy.
Guerrilla is good IF you can consistently get a Sneak off, and for using a "odd" point of AP if you have 3 AP left, or if you have no other 1 AP skills that are worth using at this time. Using Smoke fields with your supportive mages or grenades on other characters can do wonders for enabling this, as well as teleportation key targets to kill line of sight. I've put it to great use, but its much easier to utilize with Archers and Snipe. This can turn the assassinate Source ability with absolutely devastating damage though.
Glass Cannon is ... risky. I'd much rather survive a turn of CC than have one extra attack in, especially given we can often sustain our initial "burst turn" of AP with Warlord and Adrenaline if needed. Its not a bad trait for sure, especially if you have a VERY low initiative support mage who can cure any CC at the end of the round before the Rogue's next turn.
Speed Creep is definitely a luxury, and is likely better than the remaining options, although Bigger and Better might tie with it if you want to squeeze in more Dual Wield and Sneak skill, making it more feasible to use Guerrilla.
