Thalyssra doesn't, she doesn't compromsie on the demons, she doesn't compromise on the mana, none of them do - you see a substantial amount of the nobility of the kaldorei shining through, despite the bad qualities displayed in some of the Suramar citizens. In the midst of all that suffering, and pain, she still sacrifices herself and pushes on. Her condition doesn't cause her to compromise in her ideals at all. Her pride doesn't get in her way either. She sees the obvious logic and sense the highborne and druidic night elves saw about arcane addiction that Azshara refused to see, that Darth'remar denied and takes Farodin's counsel just like she later takes Tyrande's counsel.
She goes out of her way to right the great wrongs of Elisande, against her own people - both those wrongfully expelled and denied sustenance, and those attacked like their Moonguard brothers, also Suramar citizens trapped outside the shield, who should have had a happy reunion but instead were attacked because the legion needed some of hte power tools they had there.
This is admirable and a character of considerable quality. And while she is supposed to be quite powerful, we don't see her super saiyan either when we quest with her. She and Farondis are my favourite night elves of this expansion and i'm glad that they have some new night elven heroes. As much as il ike the Wc3 lot, it's shocking the night elves have had no real new superstars since their introduction in WC3. Thalyssra and Farondis are 2 of the best. Likeable as well are Valtrois, Occuleth and Lothrius.