I don't think Elizabeth was indecisive here (though she was concerning cutting off Mary's head). Rather, she did decide not to name anyone.'Discretion is the better part of valour'.
Elizabeth 1 survived as queen by making 'answers answerless.' when asked whom she would appoint as her heir should she die without issue. Drove her council crazy at times, but she knew what she was doing. We'd have had war had she said young James of Scotland.
Or named ANYONE.
I agree with Cicero, but only partly and I don't think I like him. I have decided.