the checkpoints and the loot only once per week is here. http://www.neogaf.com/forum/showthread.php?t=864776#post123373556 the VOG being 27 on normal, 30 on hard, and 31 on nightfall is data-mined. http://www.gamefaqs.com/boards/704532-destiny/69734134/791288338 raids starting at 25 or a level requirement of 2 below the raid level is implied here. http://www.ign.com/articles/2014/07/30/destiny-the-endgame-is-only-the-beginning-ign-first