By "modern fiction", or "modern vampires", I am describing a depiction of vampires where their role as monsters has been changed to that of heroes. Apparently some people call them "vegetarian vampires", though I'm personally not keen on the term.
I'm not sure when they started, but the hallmark of this particular vampire depiction is that the vampires are essentially super heroes. They have immortality, super strength, the ability to influence others, and many other desirable traits.
In stories like True Blood, Vampire Diaries, Twilight, and similar, it seems like they no longer have any significant downsides. They aren't ugly and freaky like Nosferatu. They can pretty easily get invited into people's houses (just "glam" them at the door). Religious iconography barely itches.
Even the sun, traditionally the most surefire and absolute way to kill a vampire, has been worked around. In Vampire Diaries, it's solved in five minutes by getting a witch to wave her hand over your favourite jewelry. In Twilight you just need to stand where it's a bit shady. In True Blood you can stand on the other side of extra special glass windows.
And what of the all important blood drinking, and the murder that goes along with it? Aside from True Blood's synthetic blood, why not just glam people to donate blood and drink it safely out of blood bags? Done and done.
There are still vampire depictions where vampires are still straight-up monsters, such as 30 Days Of Night. And there are stories where vampires seem to oscillate between monster and super hero, such as Buffy the Vampire Slayer (most are just fodder for being slain, but characters like Angel are essentially super heroes).
But if you are a vampire in a universe like True Blood, Vampire Diaries, or Twilight, it seems to me that the only downside to being a vampire is either intra-vampire politics, or, more commonly, each individual vampire's self inflicted psycho-drama.
Am I missing something? Are vampires in these narratives in any sort of physical duress or have any seriously debilitating afflictions that we are supposed to assume even though it's never shown? I'm sorry, but constant brooding and moping, and other problems solved with a modicum of self esteem, are just not convincing disincentives.
It seems that vampirism is just a ticket to being perma-sexy for hundreds if not thousands of years.
Why would anyone not want to be a vampire in these modern depictions?
Update: In order to address concerns that this question may be to open ended, I'd like to constrain it to the following points:
The downside must be physical, not psychological.
The downside must not be one of this list of traditional downsides that have already been worked around in one way or another in various fictional depictions:
damage caused by the sun
need to kill humans to survive
damage from religious icons
not seen in mirrors, or cameras or any indirect viewing (completely eradicated in modern depictions)
damage by garlic (completely eradicated)
damage by holy water (completely eradicated)
What does that leave? Plenty of possibilities. One that occured to me recently is that it is vague, at least to me, as to whether or not these vampires face eternal damnation for being vampires. Once a person becomes a creature of the night, is some kind of "hell" a certainty once they are destroyed? In the stories I am familiar with, I don't know if that is ever made clear.
Or it could be something else entirely. There are lots of ways to make it unappealing to being a vampire, and I wonder if it supposed to be assumed, or if it is ever stated.