First of all it's annoying that every single door is unlocked, since it makes house fairly unusable for other that simple cover, but really none secure since the enemy will be able just to walk in.

Therefore if you could lock the door you would have a "bunker" where you would be able to rearm or get medical attention in a more secure way.

Then to open the door, it would be nice with several options, like silently lock-pick it, shoot the lock to pieces the a couple of shots or just breach it with some C4.