It's an interesting concept, but if they remade FFVII for the Wii, I don't think they should use the Wiiboard.
As for the command selection, I think it's quicker to have traditional cursor (controlled using the analogue stick). The minigames would work well with the Wiimote. I think on the menu screens would be a good place to use the cursor though. Imagine drag and drop materia! I don't think they should change it too much, but enough to warrant the Wiimote.
I think if they were to remake Final Fantasy VIII however, because of the 4 command limit, they could have assigned commands to the D pad. Also, swinging and pressing the B button would replace the action of Squall's tap A and at the right time hit R2 button.
I believe that with the superior graphics of the Wii (compared to the PSX originals anyway), and the unique control system, coupled with the fact that the Wii has proven to be an insanely popular console, that if they were to remake it, they would rake in the money.