Glad this thread came back. I just recently got to watch all the episodes. I thought the second season was cool and I want to see where they are going with the "reveal".
It absolutely astounds me that people complain about retcons in a TIME TRAVEL show. If there was ever a show where retcons make perfect sense, it would be Doctor Who. And, really, what does this actually change? How does the Doctor being the Timeless child actually retcon anything? That's the part I don't really get. Nothing changes. The origins of the TIme Lords has never really played any part in any of the New Who and barely played a part in old. Why does this engender such strong reactions.
It's like the Doctor coming back as a woman. If there was any character, anywhere in fiction, where gender swapping made sense, it's the Doctor. It's really sad that people lost their naughty word over this.