Optimistically, the XB1 could have done no better than the Wii U right now, in terms of LTD simply because we would have heard something, anything at all that suggest that.
So right now XB1 max can hit 7 million or whatever the Wii U was at that time, in August if it really was Overtracked.
Realistically I would say 5.8 mill considering boosts haven't been truly factored in yet
In this day and age, with the Internet, ignorance is a choice! And they're still choosing Ignorance! - Dr. Filthy Frank