I think that it’s an interesting topic that some cards could / should be banned as signature spells. I know that its been talked about in other Commander like formats and Commander that some cards be banned just as commanders. Like always with this argument it could help balance out certain decks while opening up the format/ not constricting it as much. For example Thoughtcast on its own ISN’T that broken, but when it is a signature spell you can pull of constant turn 4 wins with Saheeli, Sublime Artificer. While an easy solution would be to ban Either of them it would be really cool to see a new ban list for signature spells to be implemented.