I believe that if Dracula was set in the modern era, and published more recently, it would be a completely different book. The female characters would be better developed, the modern setting would change the story dramatically, and Dracula would have different and better motives.
The female characters in the novel Dracula by Bram Stocker when read in modern times, seems a little behind the times to say the least, it doesn’t even pass the Bechdel test. Especially with the lack of development in the female character department. If the story was written in the modern era Lucy and Mina would be more developed, therefore making them more interesting. Lucy for example could be an aviatrix, similar to the real life aviatrix Amelia Airheart. She could be a much stronger character than she really was.
If the setting of Dracula was changed to a more modern setting, such as the present the story would alter the story and bring it to a much more open to things than they were in the book (they were pretty open for the times the book is set in). The characters, especially the female ones would be developed in a much more different and interesting way in my opinion.
Finally the antagonist Dracula would have different motives, therefore making him a much more interesting character. He could have accumulated scientific knowledge about himself and his curse, testing the limits of his body, curse and mind. He could have built up a library of knowledge over the hundreds of years of life and have his blood consumption down to an exact science. Perhaps he could even be trying to impose his “curse” on the human race as he thinks it is an evolutionary step.
These ideas, a general movement of the book into the modern era would in my opinion make the story more interesting with modern/present day ideas, motives and technology. It would improve the strength of female characters in the book, the book would have more intriguing themes and morals, and it would give rise for the better motives than there originally were.