My understanding is the m2ts is being released before the additional content will even be completed. A sort of pre-release for "beta testing", i.e. the forum denizens to look it over with a fine-tooth-comb and hopefully find any remaining issues before the final release, which will either consist of A: the additional content and bluray structure separately IF there are no issues found with the "pre-release", or B: (presumably) a full re-release with additional fix-ups to the main video/audio track, as well as the additional blu-ray features and structure.

So, there's a reason it's being done this way, and it has little or nothing to do with saving space or not making people download stuff they don't want. As you say, if that were the goal, selective torrent download would be the way to go.

- Oshyan