Aileron reversal is a very serious potential problem for most aircraft with swept wings which operate at high subsonic mach number and beyond. Due to the flexible nature of the wings, the elastic deformation at high speeds due to aileron deflection can be sufficient to cause reversal. The obvious way to solve it is increase bending stiffness but this has weight penalties, so as always there is a trade off. This has to be a significant reason to use inboard/outboard aileron configurations.
[This message has been edited by aerostude (edited 27 May 2001).]