Yes, the new version of 614.12 has rendered those old rulings inaccurate: A Hideaway land that enters under a
Blood Moon will enter untapped (though still without triggering its ability),
Containment Priest plus
Nature's Revolt will cause every land players attempt to play to be exiled instead of entering the battlefield, and
Ambush Commander plus
Essence of the Wild will cause all of your Forests to enter the battlefield as Essence of the Wilds.
However, in general we're not going to be revisiting old rulings like these and continually updating them as the rules change. There's over seven hundred threads in this forum with more being added all the time, and searching through them each time a substantive change is made to the rules in case one of them has become outdated is effort that's far better spent elsewhere.
To answer the new question, if you control
Prismatic Omen but no other lands, the Omen will not cause a
Sulfur Falls (or similar) to enter the battlefield untapped, because although the land will be an Island (and Mountain, etc.) once it's on the battlefield, it's not on the battlefield yet, so you do not currently meet the ability's conditions. (If you do control other lands, the Falls will of course enter untapped, since the Omen gives those other lands the types necessary for you to meet the condition.)