First, J. Penafiel was labelled a "royal expert", not a biographer. Second, this programme had nothing to do with bashing or distributing rumours and lies. As I said before, the whole feature was very balanced, and so were Penafiel's statements. His quotes included the well known "worse than Eva Sannum" and "granddaughter of a taxi driver" but he also said that Letizia was doing a good job and that he thought that Felipe became a much more likable person because of her.
The bottom line was that Letizia had to change her personality in order to fit into her role or what Zarzuela defined as her role (title "the tamed princess"), from an outspoken and gutsy woman with lots of nervous energy and great gestures to what we see today, Felipe's shadow - a well documented change in appearance that can hardly be disputed. Unlike Queen Sofia, who was born and raised to be a consort, Letizia had to force herself to adapt since the expected features didn't come naturally or didn't suit her personality. Penafiel did say that Sofia is the perfect Queen but also that - in contrast to the love marriage of her son - her marriage may have been a success for the institution, but not at a personal level; the fact that the marriage of the Kings is kind of an arrangement for the greater good has been well known in public long before Penafiel came up with the topic.
I doubt though that Felipe would have given up the throne for Letizia as stated in the programme, he was raised and groomed to be a King and such a decision would have broken Sofia's heart - Felipe has always been and still is a mama's boy and he would never have done that to her. And what would have been the alternative anyway, become another Duke of Windsor? It's rather plausible that after the Eva Sannum desaster the Kings didn't have any ammunition left, finally agreed to confirm the relationship and got on with the situation.
Well, I don't know, but to me it always seemed, that those series are a kind of entertainment for mostly an older generation of people here. Maybe we are so interested in other monarchies BECAUSE we have no monarchy anymore. But mainly: those series are sometimes nice to watch but IMO they are absolutely no serious journalism. Especially ZDF is very cursorily most of the time. Most of the time I know more than the so called experts in this documentaries... Except Rolf Seelmann-Eggebert, he's a devoted expert 
