Trying to put together a good Shadowblade, and traditional rogue gameplay (stealth and dual wield) doesn't look that viable. For one, it seems like the only invisibility ability lasts just 2.5 seconds, and that doesn't seem like enough time to slip up on someone and give them the business. For two, there doesn't appear to be a backstab mechanic? I'm also not entirely sure what bonuses you get for attacking while crouch-stealthed (as opposed to using a power).
Is someone further along the lines, with some idea of how these powers transform (or mutate, or whatever the mechanic is called) able to give a clearer path? Or does the Thieves Guild (or Dark Brotherhood) give a more appropriate set of skills?
For what it's worth, I can already see how a Bosmer with a bow, the Assassination line, and a bit of Shadow could stomp balls. I'm not seeing the same potential with a melee Shadowblade, and I assume I'm missing something.