Here's the thing with Ashara, the more you progress in your story the less annoying she gets. She stops mentioning her teachings when summoned and blablabla. When it comes to her combat ability, she's similar to a Marauder to a certain degree. So i don't believe she's very good for tanking, since she has no tank stance, no taunts , and wears medium armor as well as no shield. Your tanking companions are khem and boneface.