The Hound vs. Brienne wasn't fanservice. It was a natural way to end the Hound and Arya's journey with one another, while giving Brienne something to do. In the books, her arc is filler and she is just wandering around the Riverlands aimlessly. The showrunners certainly respect the source material, as they've adapted the books relatively faithfully through seasons 1-4. When they hit season 5, they ran out of good material and had to cut a lot of the fat from AFFC/ADWD. After that, they didn't have any source material to work with at all.
Olly and Karl were minor supporting characters that took up very little time. Cutting them wouldn't leave much room for other plots from the books. Jaime's revelation wasn't needed for Tyrion to kill Tywin, we don't know the relevance of the switching of the babies yet, Lady Stoneheart is a one dimensional filler character, and Show Cersei blew up the Sept of Baelor, so not exactly a saint.
Martin is more than a part culprit. If you're upset that D&D diverged from the source material, you have only Martin to blame. He's the one who failed to complete the series before the show caught up.
ASOS had a lot of material, so splitting the books into two seasons was the right call. In fact, it wasn't quite two seasons, as some material from AFFC was adapted into season 4, so your next point is also wrong. Material from AFFC/ADWD was adapted throughout seasons 4,5, and 6. Of course, they still cut a lot of material, but most of it was filler and bloat.
8 seasons and 73 episodes isn't rushing by any stretch of the imagination. Remember, it was Martin that failed to provide D&D with adequate material, so they were forced to forge their own path.
How would delaying GOT a year have helped? Martin still wouldn't have released Winds of Winter, so they would have had to diverge from the source material anyway.
Martin couldn't work the five year gap in the books, so why do you think D&D could make it work in their show?
Dance and Feast simply do not have enough proper material to create two full seasons.