the reason has nothing to do with control schemes.
It is because the Wii version was already behind, and they didn't have the manpower to get it caught up. So they just put it on hold, until they either have the manpower(and decide it is worth it to start it up again), or decide to scrap it for good.
As for why it was behind, Dennis and Jason have both said that it was behind because they were trying to convert the 360/PS3 graphics to the Wii, and that was taking longer than they had expected.
As for whoever said the DS version didn't have a civilopedia...where'd you hear that? From what every single Firaxis employee has told us(including Jason, the project manager), it is exactly the same as the console versions, except for the graphics(which means civilopedia should be in it)