Like I said the other day, without having read the script, I wouldn't necessarily blame the writing. What I might blame is unfortunate editing.
And as for Julia's interest in Barnabas and where the whole notion of having her involved with him comes from, well, I suppose it can be traced back to the exchange between Julia and Liz after Julia has just discovered Barnabas is a vampire and Liz says she's surprised because she would have thought Julia would find him fascinating, to which Julia replies that from medical, psychological and physical standpoints he is fascinating, and Liz tells her to be fascinated.
19 days 15 hours 45 minutes 32 seconds since the Depp/Burton Dark Shadows has been in release(ET)!!