All these methods meddle with films editor's jobs. And, the be frank, their job is much more important than considerations for piracy: they make the movie (or tv series) actually interesting. Making them do that (or changing their tools to support meta-data to do that) would be equal to bothering creative professionals who are essential to your product's success with mere details.
And, if I remember correctly, GoT producers already said in some interview that they're not that concerned with piracy anyway.
There's a difference between post-release piracy and pre-release bootlegging. I would be surprised if this leak doesn't noticeably dampen their view count for the first four eps. Although that's hard to measure.
Piracy is actually in their interest up to a point. It generates free advertising through free samples, and might lure new subscribers who are on the fence about buying. The endgame is they really want people to sign up for the whole package.
And, if I remember correctly, GoT producers already said in some interview that they're not that concerned with piracy anyway.