Double Cross, Mitigation Debuffs, then Dazzling Steel and Lung Puncture.. then throw in the snare for the diviniation and magic resist debuff to help others.. After that it's fairly free form.
All CAs are worth using if you can synchronize your auto attack to them, since then you don't actually lose any auto-attack. But yes, things like Impair can definitely be left off due to not doing much damage and costing power.
From my parses (STR/WIS with 2.0 delay PvP weapon, Style and Reach), ~40% of my damage is auto-attack, 6-10% is Inspiration, followed by Guile at ~5-7%. Around 3-5% then is Uncanny Response, Plunder, Whirl of Blades, then Dazlling Steel and Razorpoint.
So those are the most important CAs damage-wise. I have the Inspiration and En Garde timer reductions maxed out (since an En Garde proc triggers another Inspiration hit, it's good to synchronize them and always use them together), and I just alternate using Finesse and Ruthless Cunning, along with En Garde and Inspiration (triggered in that order).