True, I'm surprised that the show has never really examined that more closely, the writers seem to think that it's a good thing for Elena that Damon has completely written off Katherine and is willing to kill her, or that Stefan likes Elena because she is 'the exact opposite' of Katherine, but doesn't that still suggest that a lot of their feelings for Elena are tied up in her being the ~better version~ of Katherine?

The writing of Elena with Damon did damage her character for me, mostly because I was put off with how much she kept justifying when it came to Damon, but I suppose you can argue that it's been there all along, she was still counting Damon as a friend when he did heinous things to other people in the first three seasons too. And yeah, I never understood how becoming a vampire heightened her feelings for Damon, yet completely switched off her romantic feelings for Stefan? It just felt to me like it was more about Delena being the fan favourite couple, so the writers decided to drop the increasingly unpopular love triangle and go all in with that pairing, but in the show it doesn't make a lot of sense to me when you look at how intensely human Elena felt about Stefan