There is nothing wrong with Starfire. Not in my opinion.
I mean, yes, people complain of the way she's posed in RhatO and how she seems to do nothing more than fuck Roy and Jason but I feel that they don't really understand everything. Her dialogue in the comics and actions proves that she has intelligence and strength, and her flashback to her childhood shows that she has her pride and would not be belittled without consequences.
If she wanted to do both Jason and Roy(and I don't blame her because if Roy and Jason were real and I had a chance to go at 'em, I would) then she has the right to go ahead and do so, with their consent of course.
So, so far Lobdell has provided good dialogue for Starfire and decent characterisation(sexy, proud, nice, savvy and efficient; she knows how to dress in style and how to navigate her way around the human world, securing a limo and such for Roy and Jay).
I haven't seen too much emotion or interests from her, but the series is just starting out and some people don't wear their emotions on their sleeves and openly spill out whatever interests they have to their recently made friends. Also..seeing as Starfire is an alien on an alien planet, perhaps she's just using Roy and Jason to help her explore and experience more of Earth. Places that the Titans never brought her to. Jason and Roy are certainly entertaining and they do travel to a lot of exotic places.