Kingmaker's Daughter (by PG) was 99p for Kindle version on Amazon the other day, for those that are interested.
I think it's harder to make a historical drama realistic, because people know the story and have certain expectations - they know the time period, they know what to expect, the storylines, the buildings. Whereas with fantasy, you have a bit of leeway IMO.
I also think Margaret Beaufort has been acted very well. It must be very difficult for the actress playing Elizabeth, because she needs to show the power she wields without losing the sympathy for the character IYSWIM. I think the real Elizabeth was probably an interesting character, but probably had the ability to be quite ruthless and manipulative, which in today's society would make her the "bad guy" - and in this drama, she is firmly placed in the "heroine" category. Ties her hands a bit.
Yes, the princes in the tower is one of those mysteries that I truly wish could be solved without a doubt, and it just isn't going to happen. I have my doubts about Richard III being directly involved, as there are far easier ways for him to get them out of the line of succession, whereas it was vital for Margaret Beaufort and Buckingham to have those boys dead, with the added bonus for them of Richard taking the blame. I think it's telling that Henry VII (?) when he married Elizabeth's daughter (Elizabeth as well) rescinded the act that made Edward IV's children illegitimate. I don't think he would have done that if there was any question at all that those boys were still alive, as that would have put him in a precarious position. Therefore, I think he was certain they were dead, which IMO means he had that info straight from Margaret Beaufort. I honestly think it was them, but obviously there is no proof, so it's all speculation.