I could totally see a online PSO3 style battle system with this franchise. Since the card system was already in effect and the different fields, it would have been relatively trivial, and could have been a huge success.
Given the technology that the portables have now, I'd like to think that the 3DS could easily replicate something of that PSO Episode III had.
But again, that's up to Capcom. They got a lot of people who bought a 3DS thanks to the recent and on-the-way Monster Hunter games. It's a perfect setup...