These concerns all apply to existing jail breaking methods. An official image would be much easier to make obvious that it’s not the same as the non-rooted image.

In order for any of those threats to work it would require physical access and access to passwords and accounts (for example reconnecting to cloud services, restoring backups or even just unlocking the phone to perform a flash). At that point I don’t think it’s having or not having root access that is the issue.