Midnite, what you say makes perfect sense, but I still don't buy it. I think an important point of the 1795 storyline was how an ordinary, cheerful, even rather dull young man became a bloodthirsty vampire. Also, I don't think Josette would have been interested in a guy with hidden depths.
Still, I think that in later storylines the writers found it inconvenient for Barnabas to have been ordinary, cheerful, and dull once upon a time, so they made him dreamy and sad-eyed as a child. But that has nothing to do with family issues.
On Dark Shadows, reality is like Silly Putty: you can mold it into any shape you want, and then change your mind and mold it into a completely different shape.