Whether it's sci-fi or Fantasy is completely irrelevant. The same principles of storytelling apply. And the problems with the later seasons of GoT weren't the fantasy elements, but that established characterizations, plot sturcture and often logic were thrown out of the window to make some sort of fanfic that only existed to deliver "shocking" twists and "kewl" one liners for the trailers. So the problems were independent of the setting and chiefly originated from bad writing.
FWIW, I felt the main issue with later seasons of GoT was that they tried to fit too much material into too short a runtime. In order to try to make it work they made compromises, including some of the things you mention, and ultimately while the series still had some high points, the overall story and some if not most of the characters suffered for it. I wish the series had continued the pacing established in the first season.
It adds up to a Fantasy series with a lot of stuff that could be found in a historical documentary which focused on the shocking parts of history.
Star Trek II and Star Trek III were so grim in parts that Star Trek IV almost became a straight-up comedy to balance them out and end the Spock dies/is reborn and brought back story arc on happy notes. Trek is no stranger to grim. It just balances the darkness with comedic moments and lighthearted episodes and films.
That Andersen guy was also up to no good. But, yeah, if people find GoT grim I would not recommend reading classic literature, like Robin Hood, Man in the Iron Mask or any of the original fairy tales now Disneyafied. https://www.abebooks.com/books/the-gruesome-origins-of-classic-fairy-tales/index.shtml https://www.scoopwhoop.com/disney-fairy-tales-with-dark-twisted-endings/
A man with an iron mask was said to be the twin of a French king, I believe Louis the XIVth. It's a legend of course but maybe it's the truth as well, we'll never know. Was there ever a king that had officially a twin brother?
Possibly. Spoiler: Man in the Iron mask In the movie only one Musketeer dies and Phillip replaces Louis.In the book three of the four Musketeers die and the plan fails. So happy of an ending too.
Now that's just weird. But if half of what I've heard about college today is true, weird is par for the course in those places.
Yes, although as far as I remember there was no skullduggery involved. King James I of Scotland and his wife Joan Beaufort had twin sons Alexander and James on 16 October 1430. The older twin Alexander died the same day he was born, and the younger twin James became King James II in 1436.