She has one of the key jobs in government.
Nope – she’d need to be in government for that.
You have to weigh up the likelihood of them holding a certain shadow post having a detrimental effect on their prospect of getting the real gig. In Abbott’s case I would say her presence at the pointy end of the Labour Party makes it less likely they would be elected.
And yes, she is much better in print where you can take time to word things very carefully and take time for reflection (and maybe advice from others) – but that is not good for politicians who have to be able to answer unexpected questions quickly and not sound like a loony when doing so.
Granted that this is why the spin doctors try to keep questioning rigidly on-topic (their chosen topic) and feed in answers via earpiece if at all possible, but the likes of Abbott must have the PR guys tearing their hair out. You could argue that this unpredictability is a good thing, but not as part of a drive to make a whole party electable.