I would have announced a doctory male actor and a female actor so that everyone would assume she was the companion when the location photos started to leak and then do the switcheroo at Christmas and surprise everyone.
That is a fantastic idea and no doubt would have put quite a few fans on their ears. I’m very shocked at the hate for this change. I suspect it’s actually insecurity. The Who board blew up as expected.
To the point of your idea working, there was one post from a guy who had heard the news before he could see the reveal and he was asking if it actually said she was the new Doctor. She could still be the companion he said. There was an air of desperation in his post, as though the world may not have ended after all.
Where many fans feel uncertainty, possibly in their own feelings as well as the show, I feel a relief that I’ve been wanting for a few years. Relief that the show is getting the refresh it’s needed with a new Doctor, companion, and executive producer all at once. Maybe we can get away from the sappy/silly/All Existence Depends On This type of stories.