I've been experimenting a lot with Specter. I don't bother with the snowcrows rotation nonsense, my main criteria is "is it fun to play?" Here is the gist:
How to play Spectre when you are used to Daredevil: Instead of Assassin stats, run Celestial or Ritualist, instead of Eagle runes, use Firework, instead of Critical Strikes and Trickery, use Deadly Arts and Acrobatics, Instead of staff and Pistol/pistol use Scepter/Pistol Shortbow, instead of Signets and Tricks, use wells and venom (and blinding powder - nice blast finisher). Playstyle: Instead of spam 1 and spam 3 over and over, you... well spam 1 and spam 3 over and over, I guess that part hasn't changed.
For just fun running around PvE you can drop the wells, useful in zergs, not for self preservation. When soloing, go with heal signet and infiltrators so you can use 3 as much as possible. "Endless Night", the rollover skill on 3, is your big damage dealer (or barrier dealer if you are targeting an ally) especially if you have Deadly Ambition and Potent Poison on deadly arts. Assassins reward on acrobatics is excellent to keep your health up, and use the condi cleanse traits, as condition removal on Specter is severely lacking.
Have fun!