Re: Which female character shared a deeper connection w/ Bruce?
I don't think it's inherently bad that they used a made up love interest. In fact, arguably one of the greatest Batman movies ever made (MOTP) used a made up love interest and made up villain in one fell swoop.
I think the problem with Rachel lies with the casting unfortunately. But it is what it is. The character served her purpose in the plot. I don't see how she was badly written, I just think the problem with her was they never were able to fully convince us that she was worthy of the affections of both Bruce Wayne and Harvey Dent. Unfortunately that does come down to looks and casting, and chemistry too. Character-wise it was there though, as she was noble and a no BS moral crusader like the two of them.
I think given that the studio mandated they have a love interest in the first film when they weren't originally planning on it, they made the most out of it. By making Rachel a childhood friend, you lose that awkward obligatory "oh hai!" moment that would have resulted in trying to cram in a pure love interest that Bruce meets midway through the film. That just wouldn't have gelled with him being so focused on putting everything together for his mission.