Well, I see the development of their relationship like this:>During most of season 1 she see him as someone manipulable, and uses it to mostly have him do her work or to have fun, to do so, she teases him on his ego or sexually pretending that she could give him a chance.
For her Dipper is just a silly twerp, and even if she care a little about him, she wouldn't let it show because she wants to keep the image of a thought edgelord girl.
Next to the end of the first season Dipper would get tired over this and call her out in front of Wallace, that would them break with her.
During the last episodes of the first season they can barely look at each other faces, and it continues until "Into the Bunker" at season 2.
There, the Shapeshifter takes her form and she proves to Dipper that she is real by acting like her actual jerk self with him, which further makes her realise how he see her. Like with Wendy, they have that conversation together at the end of the episode, and she admits that she has been kind of a jerk to him, and says that he is a little cool and propose that they might try again. Dipper is unsure, but accept to start again with her.
Their relationship slowly gets better, as she isn't trying to play with him, and Dipper actually shows his more mature and brave side along the season. By the Weirdarmagedom they can already trust each other and it basically culminates their subplot of character development as both made each other a little better after confronting their flaws. >hook up potential
Well, I believe that after what happened, she would take a Haruko from FLCL route and admit that he is still too young for her and this was kind of a real deal on their relationship. I find it possible that Wendy might be interessed on a 16 years old Dipper, but I find Robin more likely to actually hook up with him when he is older, even if it isn't permanent.