With a weaker spine you can only build out the arrow shelf so far before you run out of usable shelf (on most bows). I personally would rather have arrows that are too stiff. I can do more with my setup to get good flight. Brace height adjustments, add point weight to the arrow, maybe use a better performance string. Or any combination of adjustments mentioned. I can accurately shoot an arrow that is too stiff. But for me, I have trouble with consistant accuracy using a weak spined arrow(especially with a broadhead attached). Now if your arrow is too weak you still have some options in reverse of adjusting point weight to lighter points, brace height adjustments or if you are shooting a performance string you can back off to Dacron strings. You can also add more strands to the string to decrease performance to allow the weaker spine. Still I like a stiffer arrow because I think it assists with the column strength of the arrow and aids in penetration for hunting situations.