Guarded: Unit cannot be targeted if there is at least 1 other targetable unit on their side of the board
This could be applied to Eredin's leader ability, Saesenthessis, and other immune units that supply the points of "no-unit" decks.
Immunity may be a problem, but it's not because of the fringe cases where players run a spell/artifact deck. Like I've mentioned in another thread. Because you don't need Saesenthessis to have a spell/artifact/control deck, changing her changes little for those decks. There is only one ST deck that goes all in with Saesenthessis and that's only competitive against control decks. Regardless, CDPR shouldn't make a habit out of nerfing cards because of fringe cases. Not only does it limit creativity but it also makes the meta more stale.