So...
I like both Rose and Martha. If I had to pick which one I like more then Martha does come out on top. Martha is the type of person I would want to hang out with and be close friends with if she wasn't a character in a TV show. I would hang out with Rose too but she'd probably be the type of friend that I'd only want to see in small doses because she is a lot clingier and likes being the center of attention. But I do like them both and I'm happy that they're both coming back in S4.
But I think I'm the only person so far who doesn't think that it's going to turn into one big Roselovefest. I don't think that Martha and/or Donna are going to get pushed to the side while the Doctor and Rose have a big sappy reunion. Sure, the Doctor is going to be thrilled to see her. I think he's going to be thrilled to see Martha again too. I think he's going to put on a protective cup before trying to be thrilled about Donna. Actually, probably just some kind of cheek guard. I also think that Doctor is going to have a lot of time to think about what Martha said when she left and it's going to make him realize what Donna was trying to tell him a year ago - he's not appreciating what's right in front of his face because he's too busy trying to live in the past.
So, my theory is that he'll be happy to see Rose and will want to find out what's new with her but then she's on even playing ground with everyone else. And I don't care how much of a hard on RTD has for Rose, I still think that it's time for the Doctor to show some emotional growth and having her come back is supposed to show he's moving on. Maybe it's even going to show him that she's not Saint Rose but just another woman like Donna and Martha and will push him to finally start moving on. People wind up wanting to glorify the things (in this case person) they've lost and I think maybe the Doctor will realize that he's been doing this.
I am also really praying that there isn't any cattiness between the women. I think Donna will meet Rose and slap the Doctor upside the head and tell him he's an idiot because Rose clearly got on just fine. I think Martha will realize that Rose is cool and is no one to feel competitive with. And I think Rose will realize that the Doctor has two companions that are looking out for the Doctor in a way she approves of and are awesome enough to be friends with. Then cue the sexy lesbian threesome. At least that's what I'm hoping. I want to see approval and acceptance from all three women and have them all realize they all have their own merits as companions.
Wishful thinking maybe but I don't feel this is going to be the apocalypse fandom is making it out to be. I don't think anyone is going to be slighted either because too much has been said by now for there to be any kind of misunderstanding by the Doctor. Donna told him he was being an idiot but she'd called him an idiot so much by the end of the episode that it lost its punch and he was also still really wrapped up by losing Rose. But now that Martha has said it to, after she put up with so much for him and even told him that she loved him, it's not something he can overlook. It wasn't something he would have expected from her which means it would have stuck in his head. And I don't see him making that same mistake again.
Anyway, that's my rambly $0.02 and we'll see if I'm eating my words or not.