Aye i do use Strategic Strike, but didn't put it in the the burn because of the recast on it, yes it very nice but only really worth it when the mob is about 10% or less. Shield Topple is half the recast time and you can use any time. A lot more beneficial in the long run.
And as to you using brutal on the last bit of the mob you really are not getting the most out of it at that time. you use brutal at the very begin because it is our strongest disc. Normally i'm in with a bard,shm,bst dps grp for burns. its best to use it first at that's when all the over crit buffs are being cast right off the back( all increase dmg %) . Like Warriors 2nd spire, bard 3rd spire, fierce eye, bard epic, shammy epic, auspice, Bst BA and CoP. all these effect the crit % for you. If you were to use Brutal at the very end your losing about 250% over crit from all the buffs i listed.
oo and update for you warriors reading over 26k dps with this burn so its good stuff. 8-)