I play my irons off a 37.75" 5 iron measured to the end of the grip. Depending on the manufacturer, that is either .5" under standard to standard length. Before I swapped out my shafts and had them cut down I had a lot of issues controlling flight. With my shorter lengths I feel like i hit it farther due to more centered strikes but also with better control.
When shortening the shaft generally they get stiffer, especially if you shorten from the tip side. But, if you swing weight it back to normal it is pretty much a wash. Irons that are built 1" over length usually have lighter heads from the manufacturer in order to keep swing weight reasonable. But adding tip weights or tungsten powder usually works out fine. Or if you don't care about the look lead tape.
When shortening the shaft generally they get stiffer, especially if you shorten from the tip side. But, if you swing weight it back to normal it is pretty much a wash. Irons that are built 1" over length usually have lighter heads from the manufacturer in order to keep swing weight reasonable. But adding tip weights or tungsten powder usually works out fine. Or if you don't care about the look lead tape.