It doesn't necessarily mean there's something wrong with your shooters. As HoofDaddy implies Shots not on target does not mean they were off target, it can mean they were on target but were stopped/blocked/deflected by an opposition player that was not the last defender/gk. But you probably know that.

To get more shots on target your guys need more space. If faced with a packed defence then playing defensive counterattacking can sometimes help pull opponents defence up the park and get more fast breaks and 1on1s - what works depends on what you think his orders are. But I do find that if it was the right choice then def c-a can produce a high percentage of shots on target even when shots are fewer - it can produce a high corner count too. Sometimes it might be all out attack or other options thats best.