IF Dawn and Ash somehow meet up again in the future, how would you expect their reunion to go?
Well, since the remakes of ruby/sapphire have been announced, I think either Hikari will come to Isshu or Satoshi and the co. will go to Hoenn to visit her. I believe they'll be watching her compete in a contest and meet up afterward and chat about their current journies and Hikari herself. Yes, Pikachu and Pochama will probably be more glad to see each other again right?
"If you attack Konoha, I will have to fight you… So save up your hatred and take it all on me, I'm the only one who can take it! It's the only thing I can do! I will shoulder your hatred and die with you! Because I'm your friend!"
~Naruto Uzumaki