Why should this matter? Well, part of the thing about Vampires is that they technically are invulnerable during the night. They are these powerful beings that have incredible strength, captivating charisma, and eternal youth. Why wouldn't everyone sign up to be a vampire then? Because you will NEVER see the sun again. The sun and you are no longer on speaking terms, and because of your choice to become a monster with all these advantages, the checks and balances of nature make sunlight your kryptonite.
Part of this shows how separated a vampire's state of being is to a human. People generally love sunlight, and need it for life. Without it there would be no ecosystem for our plants. Sunlight also reveals everything as it is. There's a safety in it. Being in the middle of a grassy field in high noon is one of the safest feelings people have. Humans need the sun. Vampires, on the other hand, needed to be cloaked in mystery and deception to get the nourishment that they need. You can't just saunter up to somebody and say "Hey? Can I nibble on your wrist I'm pretty thirsty." Vampires need to convince a person that despite the darkness, despite the lack of revealing sunlight, that the potential victim certainly is safe. Vampires can't truly reveal who they are, because what they are is so unnatural and such an assault to human morality, that no society could ever 1) let them exist or 2) keep them safe from those who felt it was necessary to kill them. This is why vampires are creatures of the night.
Getting rid of the deadly sunlight allergy, as one could put it, makes vampires way too powerful to not already take over the world. Seriously. Vampire armies would be all around us, hunt humans and farming them for their sustenance. It also shows that there is no punishment for eternal beauty and power, which would mean everyone would want to be a vampire, and no vampire would ever really lose touch with his humanity. Well, other than being 600 years old and thinking that the stuff I worry about at age 22 is extremely petty.
That brings me to ThingIHate #2...
This is incredibly unbelievable in my opinion. I don't get it at all. Let's think about this: Say I am a 128 years old with the body of a 22 year old. I haven't aged since I was 22. My mind hasn't deteriorated either. We can even say I've been able to survive daylight. Also to survive I need to continuously commit acts of assault and/or homicide. I'm essentially someone who's been murdering for over 100 years, haven't gotten prosecuted for it, and have had to stay on the run to make sure no town got used to me. I also have been able to acquire all the experiences and wisdom for someone my age without having to suffer physically for it.
Do you really think I'd be able to relate to a 17 year old enough to fall in love with him?
Why would a guy with all the experiences and troubles of a centuries old vampire fall in love with the incredibly naive junior in high school girl who's troubles are probably considered far more trivial when compared to having to kill people to survive and making sure no one knows you're immortal?
This makes as much sense as those marriages that happen between men and women who have much more than a decade between them. The experiences that either one have had are probably so vastly different that there's no way one could want the same thing in life as the other. Sometimes that's not true, but usually in successful couples you see two people who are at the same stage in life and will be moving along around the same pace. How is that even possible to achieve if the age difference is at least 100 years?
I'm not saying that it's not impossible for an immortal to fall in love with a mortal. I'm saying it's probably not going to happen between an immortal and a teenager.
This is part of the reason why the character Claudia from Anne Rice's Interview with the Vampire was so intriguing. Claudia was made a vampire when she was a little girl, and kept that body. Her brain continued to age with wisdom that surpassed her looks, and she began to resent it. She was no longer a little girl, but was easily perceived as one. In her mind she understood about sexuality, deception, philosophy, and all those other things adults ponder about, but she would never look like the adult woman she really was inside.
The character flaws that need to be inherited to be a vampire are part of the reason vampires are followed in numerous cultures across time. There is a price for everything including eternity, and the idea is that vampires have to pay that price every single day of their lives. Stripping that price away to make some teenage love story full of angst and danger takes away what made the myth so strong in the first place.
So do I have a problem with shows that have vampires in them? Of course not. I mean, not that I was a Buffy fan, but I did watch some of it and those conflicts made the show interesting. And yes, vampires can definitely be sexy. But the Vampire Diaries shows a disturbing trend in the lore, wear suddenly all you need to be perfect is to be a vampire. Vampires need to be seemingly perfect, but incredibly flawed, like a dystopia of the soul. That's what makes them worth caring about as characters.