So I haven't won with this guy
yet, but I've been having a blast so I thought I would share the build I'm using. There is something kind of magical when you combine a couple of mediocre elements into something greater than the sum of its parts, in this case the Higher race, the Steamroller Prodigy, and a Shadowblade without the ambush tree.
The basic idea is to max the following skills: Rush, Essence of Speed, Blinding Speed, Momentum, Highborn's Bloom.
Also useful are all the instant cast buffs: Willful combat, Deadly Strikes, Perfect Strike, Time Shield, Blinding Speed
So here's the deal, normally steamroller burns out rather easily, you don't have much time to kill, and every rush costs quite a bit of stamina. By the time you get the damage bonus up to 100% you are out of stamina. That's where the Higher comes in, Highborn's Bloom may only last 6 turns at 5/5, but you are going to stretch those turns incredibly far with the Shadowblade's speed, and you can burn targets down quickly while using all your combat techniques for free. On top of that you can get more attacks in during the 2 turns you have to kill your steamroller target. Did I mention how many instant cast skills you can cram into your first turn after activating Bloom? you can easily save 100 stamina just on the instant stuff. Steamroller isn't just about chain rushing, it's a 100% damage boost which is very sustainable during Bloom, and gets ramped up faster as well. The speed bonuses also mean enemies don't close into melee range as quickly which is great since you need a gap to rush, ideally you would rather rush than bump attack. Everything about the build works together to cram the maximum damage into as few turns as possible and lets you burn more stamina worth of skills than you actually have in stamina.
Steamroller can be weak against bosses (unless you run into them while ramped to +100% damage) but Shadowblades are already great at single target killing with Cripple, Deadly Strikes, and Dirty Fighting unloading a ton of burst. Plus with Bloom you can burn all your cooldown attacks like Whirlwind as extra damage without worrying about running out of stamina. And Bloom is pretty useful if you have to hit and run.
Two weaknesses of the build:
1. It's fragile, typical rogue HP and lack of stun resist. It works best bursting with Bloom then retreating so you can cover your offense with shielding runes, heroism infusions, and time shield.
2. It doesn't have much mana. I ended up pumping willpower because I unlocked the divination tree and premonition + essence of speed will eat your entire mana bar. Luckily you don't need mana for much except teleport/phase door/Time Shield, and Time Shield will usually be cast during Bloom. I turned off Shadow Combat to be sure I have mana to escape.
Steamrolling around with Bloom has been a ton of fun. I started this build just trying to win with Shadowblade without cheesing ambuscade, but was still finding it rather boring until I took steamroller. This wasn't a fully planned build or anything, so I only listed the essentials. In hindsight there are a lot of variations that could be interesting, especially with all the generic points shadowblades have. Harmony or Light both could be promising and would require less mana than divination. If I had planned the build from the beginning I probably would have gotten Steamroller first at 30 and would have tried to have momentum and blinding speed by then.