| Raishi Kytori |
Gooooooood morning possible follower of Shadow! Sounds like you've got the right mindset to be effective in combat with your Ninja, however you want to take her on her journey. You've hit the nail on the head as far as damage, as most of the time your max damage output will be as a result of a sneak attack. I'm currently 4 levels into my Ninja running the AE of Rise of the Runelords and I've got to tell you she was a CORNERSTONE of our party during the Thistletop raid.
If you want to go shadowdancer, don't let an overwhelming choice between feats deter you. You may be overlooking that Ninjas get access to Ninja Tricks every even-numbered level. What I did for mine was take Vanishing Trick at level two ("Woah woah woah, you mean to tell me this grants me Invisibility as a swift action on command, denying my foe his Dex bonus to AC, adding +2 to my attack roll, AND gives me Sneak Attack damage as a result? Yes please, sign me up twice.") and Bleeding Attack, which deals 1 point of Bleed damage every turn for each Sneak Attack die unless your foe makes a DC 15 Heal check (which they rarely do in the middle of combat)....so yeah. With just the base Ninja Tricks you'll be throwing out some pretty legit damage if you fight smart and use your assets wisely. (Nothing is stopping you from pumping some points into Bluff as well. Ninja's get a TON of skillpoints per level, and a high Bluff stat gives you the option to Feint attacks [Denying foes Dex bonuses to AC, giving you the option to Sneak Attack right in their faces!])
I actually have my ninja running with a Katana (Masterwork, 1d8+6) and a Masterwork Cmp Shortbow Str+4...but then again she acquired a whole bunch of loot that the rest of the party didn't see from adventuring (It certainly helps being a ninja in a party with no other rogues, you also are going to be the main Disable Device/Perception skillmonkey....)
I don't know if this helps you at all on your overall inquiry, as this is my first post. I hope it was at least a little insightful and helpful!