The difficulty is somewhat eased if you have written a bitboard engine yourself. Is application-specific knowledge against the “rules of reverse engineering”?
>The only interesting possibility would be from the playchess community that does it in order to add or tweak terms for rating potential. But that will do little for the general community or improve general knowledge. I don’t see why not. If there were a programme that allowed R3 terms to be tweaked (ideally it would modify the executable, but with sufficient encryption this might be dodgy, and so a runtime solution would be preferable), it might be quite popular. Admittedly, making an eval-tweaker is substantially easier then recovering a working source via RE.