Just beat the Sand Demon at 27 on my Watchman-specced Sentinel, without having trained Pacify or the other 27 skill-up. Took two tries. He isn't hard, mechanically, but he does hit like a truck.
First try, I sent Kira in to let her get aggro, and then went in. Kira was basically dead instantly - her gear is mostly quest stuff. I basically kited the Sand Demon around after Kira died, but he finished me off with around 15% of his HP.
Second try worked for me. I jumped in with Saber Ward up, got aggro and kited the demon around - as the demon followed me, Kira followed it, and thus didn't stand in the AoE too much. I hit Call on the Force as soon as ward dropped, and used Stasis. Popped Zen and stacked up my DoTs. Put up Saber Ward again, and just kept moving.
Kira died when the demon had around a quarter life left. I was still in good shape. Put up Rebuke and kited the boss around - burned him down at the end with Master Strike and Blade Storm. I ended the fight with 20% or so HP, without using a medpack. My Sentinel is in almost all blue / orange stuff, so good gear - Kira was in almost all quest greens (a couple from Nar Shadda >.>) and an epic I got as a drop.
Tough, but not un-doable. I'm not really lookin' forward to Angral though >.>