If it's the same battle system as we have now, slow fast moves and fast charge moves are probably going to be the preference. Slow charges like Outrage, Shadow Ball, Solar Beam etc. will be completely worthless because the opponent can dodge them easily.
Other interesting factors would be whether it's DPS or TDO-centric and how switching works. The PvP tierlists would look very different depending on how it is. Regardless, I'm not too optimistic about the whole thing if they don't introduce any new complexity to the battle system. A tapfest to compete in which one deals damage faster or several minutes of Blisseys, Lugias, Ho-Ohs trying to outlive each other both sound to me like I want nothing to do with it.