Fear change to the old rule

Hello,

Personally I found the old rule of fear more immersive (moral test before charge with a penalty in case of failure). Is there a particular reason for changing it (imbalance)?

I am considering playing a variation that would say "If you are meleeing a model with Fear, you must first take a morale test. If you fail, you have -1 to hit" to simulate reluctance and fear in the attacker's gestures (he trembles with fear and hits badly).

What do you think? Could this cause a problem with some units / rules?

Thanks
Regards