1) You HAVE to be level 50
I was just barely level 49 when I did it on my Sentinel.
I also didn't have T7 all that greatly geared since I had not used him since getting Kira, though you can get him a set of free armour in the Dark Temple before the fight as mentioned by another poster (I didn't get it until after because I didn't play with the puzzle long enough to set it right). My character also wasn't too greatly geared, at least that's how I felt about her gear, because I was rushing to get her story done before my game time ran out. Honestly, I didn't find the fight hard but everyone has their own view of what's hard and what's not and no one view is wrong. The only thing that got me was the adds because I wasn't expecting that and I lost my focus on the real enemy so I did die the first try. The second try, I knew to not focus on anything else so it was fairly easy to beat him down.
I should also point out that I probably was using an endurance stim, as I normally do for boss fights. I like my endurance stims, they're sooo good.