I do not find it strange, Slaanesh has always been the GW least favorite Chaos God and that has been shown systematically throughout their work across all games and all lore.
I am honestly amazed we got such a beautiful model line, but absence of any new novels for such a massive and beautiful release was truly sad event. Lumineth are on their third full novel, we nothing. Considering that imprisonment of Slaanesh was set up as big plot device from start of Age of Sigmar, the fact that actual children of Slaanesh are walking the Realms should be a massive deal.
Also, I hope that the Twins are not in Broken Realms Kragnos book only to be stomped to ground by Kragnos or Kroak.