Let the unhooked person lose collision
This is really something i would like to see as it makes tunneling a bit harder. If survivors should not have free escapes, then killers should not get free kills by bodyblocking you right after the unhook. Especially for situations where a survivor successfully unhooks alone, the unhooker eats a hit before or during the unhook and in some maps the killer can easyily block the unhooked person from going anywhere.