I'm not saying Taken couldn't spawn in PoE, I'm just saying that seeing enemies or bosses get Taken in PoE is unlikely. He could invade the Prison but there's really no reason to especially while he's busy waging a system wide war against every non-Hive entity within it. From Oryx's perspective it's probably a waste of time to spend much manpower on the Reef when there's nothing notable left to Take in PoE and when he's already killed or Taken just about every Reef warrior of note during his fight with the Queen above Saturn. Keep reading the Book of Sorrow though. Really interesting stuff that gives a lot of insight on Oryx, the Hive, the Traveler, and the nature of Light and Dark.

You are definitely right. I do hope there is more story driven pve content prior to destiny 2. I'm really interested to learn more about the stranger. She was not forged in light, are there more like her? Who was she talking to? Looking forward to finding out. I love the lore of destiny. The book of sorrows totally changed how I view the hive.

There are some theories floating about she's one of the old ever of the Ishtar collective. Maya Sundaresh specifically. We know they experimented with the Device and with Proxy bodies in the past. It not hard to imagine the proxy bodies were the precursor to the Exo.