I would put money on Wiggins leading Sky at next years Tour, think he will be put in the driving seat to defend his title. What that means for Froome is difficult to gauge: Brailsford has talked about winning all 3 GTs in a year as an ambition (albeit a very grand one). With current personnel the most obvious choice would be to put Froome as leader for the Giro/Vuelta and Wiggo for the Tour.
However given the likely brutal nature of the anniversary Tour, taking Froome out of the tour team will massively dilute Sky's assault. Personally I think they will try to copy this year's effort as closely as possible, so their 'A' team for the Tour and more opportunistic assault on the other two. That could all change depending on who they sign of course.
Personally I think divide them and build seperate teams around them, Sky has the strength to do it, but I just don't think they will want to leave things to that much chance. They will want the Tour the most of course: would Froome be willing to ride for Wiggins again, and will they play it more by ear and see who has got the strongest legs after a week?
Pure conjecture is fun