Really, it would've been about the same.
Johns/Lee Justice League would be the big hit.
Batman, Detective and the Green Lantern books would've still been doing great.
Johns on Aquaman would've still pushed him up.
Wonder Woman by Azzarello would still garner attention.
Action Comics #1, Batman #1 and Detective Comics #1 would still be big sellers.
The new B-list and C-list titles would've still fell off and got cancelled.
The only real difference, I think, would've been the sales of the Superman books after the first issues.
And as Darknight Detective mentioned, the reboot really increased sales line-wide.
So, I'd wager that the big books listed above would've had 10% less sales than they did, while the other titles would've had about 25-40% less sales (with the B-list and C-List titles being around 40% less).
But it really depends on the marketing they used.
Justice League, Batman, Detective, Action, Aquaman and the Green Lantern titles may not have really seen any difference in sales.