Barriss anchors my squad, but man, I love Luminara. When you get good at GW you can farm her fast, I have her at 4* and she heals well, can ability block and hits like a tank. To give you an idea, with both at 4*, Luminara's basic attack does DOUBLE the damage of Barriss's. And her special can crit for nearly 3k. In fact, she hits substantially harder than Dooku and other well-known offensive types.
And this is below level 50, without epic gear, and only 4*. She's a keeper.