Good question. I have no idea how online is affected by controller port and online grab priority sounds hard to test. Even if you had two Wiis in the same room connected via wi-fi, the two systems probably wouldn't recognize simultaneous grabs even if you press the Grab buttons at the exact same time.
FSA, however, can easily be tested online. The timing isn't tricky at all, and anyone with a wi-fi buddy can test this. Somebody give it a shot - I'd be interested to know. I myself, though, don't have a wireless router, so Wi-Fi is a non-option for me.
As for Nintendo fixing the lag, don't count on it. They've become such a money-grubbing, casual-whoring company since the Wii's launch that I honestly expect nothing from them. They've abandoned their dedication to the gamer with expectations and reasonable standards for how a game should perform. If Nintendo fixes Wi-Fi, it'd be a miracle.