"Rose and everyone else," versus "Martha and everyone else," what's the difference? There are just as many Martha fans who like to see her as the ne plus ultra of companions, and insist that she's the most awesomest of awesome ever, regardless of how this assertion is or isn't backed up in text.

I don't think making a sharp breaking point between Rose and the classic series companions was avoidable, given how radically different the portrayal of the Doctor/Companion relationship was from how they'd previously been shown. Some of it is probably attributable directly to the Doctor's state of mind when he met Rose, versus anything inherent in Rose herself. The Time War had changed him radically and irrevocably.

Do I think the writers did Martha a disservice by essentially using her as a case study of 'No, not every regular companion from now on is going to be a romantic interest for the Doctor'? Absolutely. I was really, really looking forward to having a Liz Shaw (or even Zoe) type as the new companion based on the way Martha was being talked about before the series started. What they promised and what they delivered were two radically different things. I don't think Martha had to be in wub with the Doctor to have done the things she did: in fact, I think the unrequited love angle diminished her character significantly. And I think the whole whiny-teenager manner in which the unrequited love story was played is what turned a whole lot of people off to the character.