Don't get me wrong, Romero is the king when it comes to this genre and I accept his "evolving" "smart" zombies. I don't like it very much (I wouldn't do it if I was a writing a zombie story), but it's him and I accept it. Once you start to introduce vampires and other undead creatures I start to cringe. I'm fine with him writing these stories, of course, but why does it have to exist in the universe of the films? Can't it be something new?
I read a free comic book day comic back in the day (Last Blood I believe it was called) that did something I really liked. The "zombies" in the story that were destroying the world were actually feral vampires. So hungry and deprived of food that they became "sick" and started infecting normal people without thought. It became so bad and out of hand that the remaining vampires fought against them to protect the remaining human population. I thought that was a really cool idea.