Normally I don't pay attention to ign or other big review sites. However they did confirm just today that the new exotics we are getting in house of wolves will drop not only in PoE but in the 2 previous raids as well.
http://www.ign.com/articles/2015/05/08/destinys-new-exotics-will-drop-in-old-missions
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You misread. It won't include HoW exotics, just the old exotics at the new HoW level.