I agree, I've been looking around for more heroes that were not announced yet, and so far, there are very few models that actually have use of CP.
KoS on foot: has a general limitation (and he's waaaaay to fragile to be a general, he's stuck in AoS 1: a borderline useless low wound charcter)
KoS on horse: can use his command ability without restrictions.
Lady Olynder: has to be the general for her command abilty. Wouldn't be surprised if she HAS to be the general when present (like other mortarchs) and has this weird wording about having other friendly models that have the command ability.
My educated guess is that all characters in the army might get this "no rest for the wicked" command ability and that this will become the equivalent of the nighthaunt "deathly invocation", but costing CP (in the same style that Legions of Nagash come with a special command ability as an army trait: endless legions).
And if you slap Olynder in there, this "no rest for the wicked" daisy chains through your army.