The way Kirk died.
I think the way Kirk was killed off was BS. It wasn't like Spock giving his life for the Enterprise. It felt like the producers at the time wanted to get Kirk out of the picture so Picard's character could stand alone. Like Patrick Stewart could not hold his own with Shatner. Well those producers nearly ran Trek into the ground and they got their just rewards. They have been wisely kicked to the curb.
...TO EXPLORE STRANGE NEW WORLDS...