I have been reading the Sigvald Novel, and it made me think... Sigvald needs some love (I know so does all Chaos) - I mean Slaanesh weeps at how much love he needs.
So I think there are 2 things he needs, first just a generally higher statline - he should really be one of the best duelists in the game and now he is just kinda a better Chaos Lord on foot, I guess this is a holdover from a more conservative approach in earlier days of the game. Second he needs an aura like Morathi to debuff an area around him to represent his beauty, maybe it would be weaker but also buff units related to Slaanesh a bit (or increase their MA and reduce MD, for example +4 and -2).
If his vanity could be done somehow that would be interesting but can't think of how without being super annoying.
Anyway what do people think about Siggy, any ideas?