I'm not aware of the stolen documents issue.
My biggest concern is Kavanaugh's position that the President has discretion in what laws the president enforces. From my reading of the constitution, there is no discretion. It's one thing if the sitting president takes the position that he doesn't have to enforce a law he doesn't agree with. It's quite another if a Justice of the Supreme Court holds that opinion, especially if there's a chance he can sway a majority of the Court to agree. Especially when there's a president in office who has demonstrated dictatorial leanings.