A young vampire Barnabas would not have had credibility or weight to him. It's only the present times where casting people universally decide to throw credibility aside in favor of dreamboat hunky cute actors. That's today's Hollywood environment. To some extent it always happened, but not when creative people who cared about drama were in control.
I just cannot care about a young actor, hired to look like and serve as a romantic lead, playing Barnabas. Vampires aren't dreamboats. They're walking cadavers with, we hope, some remnant of a human soul inside, struggling to stay human. They should look battered and ravaged and dragged to hell and back. They should also be worldly, not youthful.
Now... if viewers can make their way through all that, and still find someone such as Jonathan Frid's Barnabas a romantic figure, then that's great. That means you appreciate the darker, more 3D kind of romance. You need to accept him with warts and all, though.
I don't blame Johnny Depp for his fannish desire to be Barnabas, but if he does it, I think he'll have abused his Hollywood power to foist yet another depressing wrong-headed remake onto the culture. We should wall off Hollywood like NYC in Escape From NY....