(It does look like she staged a murder scene from her books intending to frame her husband then came to her senses, doesn’t it?)
The problem is that if you recommend the book for it's "unique plot twist", the reader will keep looking for clues on how the resution may not be the most obvious and figure it out pretty fast. Then it is actually no surprise at all anymore. At least this happenend to me.
It would serve the book better if it was recommended as a great (but traditional) murder mystery novel and that's it.
I read it making my way down a random list of "greatest books of the 20th century" without any expectations; I should probably offer others the same courtesy.
That was never going to work. The husband had an alibi, and the daughter was present. Christie would have known that.
She used the mistress' name when checking into a hotel, which implicated her in the incident. If Christie intended to frame anybody for anything, it'd be her.
It looks to me like she intended to leave, considered suicide, aborted the attempt, then tried to improvise a vague story for wrecking the car. I don't believe the fugue-state part.
Sure, if that's what you want to see. Or if the tabloid journalists of the day, who even by contemporary standards behaved themselves professionally with serene disregard for anything resembling honesty or morality, think it'll sell more papers to make it look like that.