I gave Call of Duty 3 another go. In one ten minute play session, I watched half my squad walk through a wall, and was seemingly assasinated by a sentient packing crate (I assume that this was an enemy clipping through a crate, but all I saw was a wooden box with a muzzle flash). You can no longer jump from crouching (which makes precisely absolutely zero practical fucking sense) and, sin of all sins, none of the cutscenes can be skipped - and the one from the start of the level plays every time you load.
Also, you can no longer perform the screw jump attack, and Mother Brain is no longer the bad guy. She has been replaced by a new character called Hitler.