After the departure of Rose, the Doctor decided to mope. And mope and mope and mope. His moping meant that Martha really never stood a chance. Episode after episode he kept reminding her, and also the audience, that she wasn't Rose and that he didn't want her around. It took almost half the season before he finally accepted her as his companion and by that time the damage was done and the audience just didn't take to her. I think if the Doctor had been more accepting of her then so would the viewing public.
You're right there. The writing really didn't help and nor did the Doctor's feelings towards her. It also didn't help she was another one lusting after him. So because of these reasons I am unfortunately one of those who doesn't like Martha much. Or her family
