I'm no stock bender, but I am a Master woodworker. You could start you analysis by looking at the area where the bending would have to occur. There are basically two issues. One is how long and consistant in section is the handle section, the other is how well does the grain run straight through it. Either a lot of changes in width (like a pistol grip), or grain that is diagonal to the main flow of the shape or the axis of the bend, will greatly complicate the bending. Constrictions are both stress risers, and points where damage may occur to the wood due to the concentration of force they would dictate. The ideal shape would be something like a straight grip stock like a British double. Just about anything can be bent but the less ideal the circumstance the cleverer the tooling etc... would need to be.
Other factors are such maters: as grain orientation (flatsawn, riff, or quartered relative to the axis of the bend); whether the wood was kiln dried, which is bad for bending, but would presumably not be done to many premium blanks because it tends to kill the subtle colour; does the realignment require a double bend to maintain the comb angle, vs. something like an offset measurement; how severe is the bend relative to altering other measurements like butt plate alignment.
