Malekith: Very nice. The S5 T4 really lends him uniqueness. Being able to field him without a Dragon and on different mounts is also a valuable feature which mitigates his crappy save against magic - and the two new old items Spelleater Shield and Circlet of Iron just make him even better at withstanding magic from afar and dishing out destruction himself. A real improvement over the previous incarnation.
Morathi: Being able to choose between the Darksword and Heartrender is a bit superfluous, I'd rather have seen the Darksword in the normal magic weapons list or maybe even available for Assassins. Oh well.
Hellebron: Really neat.
Malus: I am not at all happy with our iconic Dark Elf anti-hero being... merely a hero. Malus deserved more than this after all the hardships he has gone through in the background.
Shadowblade: They halved his attacks from 6th to 7th edition and gave him the somehow crappiest toxin available to the temple. He should at least have gained the Rune of Khaine to be able to climb up to 7 attacks. The downgrade from Lord to Hero is a good feature, though.
Lokhir Felheart: I could honestly have done without a completely new hero. His rules may be nice but I'd rather have seen one of the following two gentlemen make a "proper" hero appearance instead of the "champion with ambitions" version we got.
Kouran: He was a Lord in the last edition for Khaine's sake, with stats rivalling that of Malekith! And now he is worse than a hero. Not at all happy.
Tullaris: Was a hero with 4 attacks back in 6th edition additional rules (and wielded the Executioner's axe and the Black Amulet and had killing blow against anything for 200 points or something). His new version does not even deserve the term "Master of Executioners".
So... actually the level of content decreases from top to bottom.