They changed all three characters for de. They removed Stefan as well as getting rid of his humanity and making him the 'bad bother'. They tried to make Damon a Stefan 2.0 because that's the only way Elena tolerates him. And they turned Elena into a Katherine 2.0, using and manipulating Damon and bouncing from one brother to the other when she feels like it.
Not to mention they completely swept all of the **** Damons done under the rug like it never happened, and Elena seems to have no morals or self respect left.
THIS. Especially the bolded part. I remember somewhat 6 months ago I said that the worst thing to ever happen to Elena is for her to be turned into Katherine, because it would ruin the whole sense of the story, because the idea was them LOOKING alike, but being DIFFERENT. I do like Katherine, but it's obvious that she and Elena were not supposed to be the same person and that Elena's feelings for Stefan as well as her friendship with Damon should have been deeper than Katherine's games she liked to play with both. Yet what we see now is Elena doing the same as Katherine, not to mention how all three characters had to be changed for the sake of DE happening. Damon's issues and actions were never addressed, writers didn't want to give him a redemption, instead they made Stefan bad
They ruined the dynamic of Stefan/Damon and as someone who liked all three characters I feel like this show made all the possible mistakes with them.
If they'd taken their time, explored the darker aspects of Caroline's vampirism and Klaus' desire for family, bridged the gap between them a bit. Evolved them individually as characters before bringing them together as a potential couple.
I do see your point here
That is actually what I wanted as well. I felt like Tyler doesn't let Caroline's vampire nature be explored because with him she was reduced to a love interest and I supported the idea of Klaus/Caroline as some sort of an evil mentor teaching this good girl about her dark side that, lets face it, is there because she is a vampire. But instead we have Klaus turning into an idiot who acts like a 14 years old teen and draws hourses. Whereas Caroline falling for him romantically at this point would make no sense whatsoever. But then again, it is TVD, a lot of things there don't make sense and characters tend to be re-written in order to fit the storylines that writers force on them when a good tv show should make storylines fit characters instead.