Your question is vague. You're not dropping something off a cliff it's moving and 400km up and 25,000km/h.
Any object coming from the ISS will be going 25,000 km/h. I don't think "aim" is the word since the Earth is moving rapidly beneath the object. There's no stationary point to aim at. Plus once the object of whatever shape in the atmosphere drag which causing friction to burn it up is not controllable. It would break apart and each object with different mass now has its own path and velocity.
I'm amazed any of it works as well as if does now.
Anything released from the ISS will initially be in an orbit very similar to the ISS. That's because the initial difference in velocity between the object and the ISS will be measured in meters per second or less (which is small compared to the orbital velocity measured in kilometers per second).
Then the orbit of the released object will start to slowly decay because of (at that altitude, a very small amount of) air resistance. The details of that depend on the shape, size and mass of the object. It can even depend on unexpected solar activity which can cause the Earth's atmosphere to puff up minutes[1]. The ISS counteracts this by periodically boosting its orbit.
The longer the orbital decay takes, the more the uncertainty adds up. The fix to accurately "aim" an object, is to strap it to a rocket and perform a deorbit burn, to slow down from orbital velocity. This way the reentry process can be more reliably aimed at the middle of the Pacific or something like that. But that's expensive.
It might not be easy to aim anywhere if the object is expected to do multiple rotations around the earth before ending up anywhere. It would be good to have confirmation from a specialist.
I agree: specifically, I think that controlling the point of impact is possible but requires equipment (rocket motors, a heat shield, navigation computers) which of courses costs money to get into orbit and can be used only once.
