Well, the producers will probably make them best friends, but I think in real life, there would be some animosity. Regardless of how Misty feels towards Ash, she's gonna be a little jealous of everything that Ash and May have seen and expereinced together. Plus, remember how Misty was in the beginning with Ash? She doesn't have much tolerance for beginners, and that's what May is. I mean, Misty probably has the most hands on training experience than any of the current people traveling with Ash, except for maybe Brock, but he was never a big battler anyway.
THe way I see it, new clothes=permanent stay. Or at least a very long stay. Which I am very happy for. I missed Misty so much, although it was worth it to see her at the gym. She finally found her place, then her stupid sisters pretty much kicked her out. A big part of this may be bias, but I think Misty is one of the most deep characters on the show. SHe's a runaway who is desperately looking for companionship and to prove her worth. She's had it harder than Ash has for sure, but Brock also had it hard, but I think Misty has more depth. SHe puts on a big independent aire, but really she's very dependent on her friends. That's why the gym was so awesome for her, she was able to see that she doesn't need Ash and Brock there constantly. Hopefully, regardless of shippy stuff, Misty will become truly independent and after Hoenn she'll go back to the gym and show her sisters how much she's grown and gain control of it. She deserves it, and it's unfair how her sisters treat her.
Wow, that was long.