If the page split is done by hand, there should be an option to rotate the page according to the line of the splitting. Right side of page can be deskew based on line of split on the the left side of the single page. Left side of page can be deskewed based on line of split on the right side.
Why do I want this feature?
I plan to split pages using scantailor and output them after this step itself. Then I plan to straighten them using android app "vflat" since I find that using this app I can easily "flatten" the pages automatically. But vflat doesn't allow to split photos which are not clicked by the app itself, hence I want to use scantailor only for this step.