Binged the TV episodes then the manga. The arcs up to the basement was awesome.
I don't want to see Eren become the villain. Sure the theme about the series is that the world is a villain, it is a cruel merciless world, but you saw it through the innocent eyes of Child Eren growing up. To see him become a monster himself was a horrible feeling.
Some things don't make sense, are probably plot holes. Ymir never getting the abilities of the Jaws titan, Mikasa beating up Eren as children (throwing him against the wall hard enough that all his firewood scatters), pure titans drinking spinal fluid but not changing immediately. Worst of all, Eren figured out that he can command titans when he makes physical contact with a person of royal blood, but never teams up with Historia to test/use this power... but he'll risk it all on Zeke's plan because he suddenly trusts Zeke more than the Armin & Mikasa (as if Zeke isn't a slave himself to his father's ideology).
Zeke, despite being very intelligent, is also too much of a risk factor that you'll never know if you can trust him or not, no matter which side you stand on. He's probably like his tall female follower that will kill allies at a moment's notice to gain favor with a new side.
But yeah, most of all, seeing Eren become a villain and mistreat Mikasa\Armin after the series had built the audience up to be sympathetic to their plight for 70 to 100 chapters, that just hurts