Well just tried this with all 29's. Sage, Sentinel, Gunslinger and myself (Vanguard).
I thought this fight was tough right off the bat but doable.
Unfortunately, it took 3 attempts (wipes) before the sage in the group tried long term cc.
Nobody else in the group had any long term cc.
Sage did not use Force Armor on anyone I could see (at least not me).
Poor sage got all huffy though because somehow by my tanking 5, (mind you this was pulling the 3 adds off the healer because he opened with an AoE)...it was my fault. I did pop all my cooldowns and made sure half the party got away...but they didn't bother coming back so I self rezzed back at the base.
Best I could do was keep 5 or 6 on me and hope that the DPS in the group could drop 1 or 2 of the weaker mobs. But it didn't happen.
I'm definitely coming back with a different group and set up and try some of the alternative tactics though.
Slingers and Sentinels can CC mechanicals. If there were droids(as this thread seems to indicate) your Slinger and Sentinel were being idiots for not CCing them.