Although it came 5 years later, this was the actual sequel to Dracula, starting off with the deaths of Dracula and Renfield. It's slow moving, and not particularly interesting, but the subtext has fascinated analysts to this day. There were suggestions of lesbianism in the script, but by the time the film made the screen, the Code had taken care of that. So you have to look pretty hard to see it. But once you've seen it, you can't shake it. Dracula's daughter, Countess Marya Zaleska (Gloria Holden), wants to be freed from the curse of being a vampire, but her impulses get the best of her time and time again. A couple of her victims are women, and the element of seduction which underlies so many vampire stories is here as well. It has also been argued that the isolation from society the Countess feels reflects the status of lesbians at the time.
All of this is enough to get us through the short running time, but don't exaggerate its greatness. Eventually, movies got more explicit, and subtext often moved to context. I saw 1970's The Vampire Lovers at a drive-in, and it was filled with nudity and horseplay among the women. But in fairness, it wasn't any better than Dracula's Daughter ... nudity didn't guarantee quality.
Here is a scene from Dracula's Daughter, where the Countess takes a woman off the street to pose for a painting:
And something from The Vampire Lovers: