I am level 40 and I have found some end of story situations particularly difficult. Typically when I use Risha my surviablity AND the surviablity of my companion is much better especially against a boss. However there have been a few situations where I use Corso & his grapple. He can grab a high level NPC with is harpoon & it has not aggro'd the other NPC's around it. Then I can kill them off as I see fit & do not have to take them on all at once & worry about using flash grenades etc. None of the stun effects so far, except droid slicing, last long enough top really do much good on higher level NPCs.