If you have played the DOOM 3 alpha you will know that the doors open automatically, unless they have a keypad and require an access code to be keyed in: then a console is activated.
Also, you can't back up against a keypad and drop lower your weapon to key in the code. You have to be looking at the keypad for your weapon to automatically lower.
"Use" keys are a silly idea: just a waste of a binding/key. It is much better to have the door auto-open or require an access code. The latter removes the silly idea of collecting ONE key from a remote location to allow the former to occur with ONE locked door. It just doesn't make any sense at all. But an access code... Hmmm!!!
And operating an interactive console/keypad just seems more immersive to me for single player. Multiplayer will be a different story: "USE" keys, keypads and interactive consoles will slow the gameplay of a DM down.
I think JC is doing this whole door thing correctly, and I can't believe so many people are discussing it so seriously. The DOOM 3 alpha runs smoothly and the doors do not hinder the flow of the game, if it can be called a game. The final product will be even better.