If it becomes critically and socially acclaimed (ie, is genuinely good according to the masses) then I think it will do better than FFXIII, which garnered 7.5m based on the table in the opening post of the thread. 10m, I think, is a good target but not a good requirement to be considered a success.

Sidenot: I always find it odd that sales for FFXIV are listed so low when there are allegedly 5m accounts created for it. I wonder if the sales are only for physical copies and not downloads.