I believe that since it takes double the speed to move normally in half speed, actions must also take double the amount of force to perform. That's why attacks hit harder if they are faster. Therefore, you are more powerful in slow motion.

Since stopped time must be near 0x speed for anyone to move inside it, any actions in stopped time must be infinitely fast or powerful.

Also, in half speed, everything would be twice as heavy, as they require twice as much force to be moved by people in half speed.

This means that you would be stuck in place in stopped time, as the air particles around you would have infinite weight.

I feel like this isn't new to anyone, but it was to me.