Some doors

Yes I'd forgotten trapdoors that's a great point.
Perhaps also a Pivot property that could be set for both windows and doors, eg left, mid right. I'm thinking for windows to tilt open from the mid point like below, also it would be fantastic with a dungeon wall section for a secret passage as you said.

That would be a nice addition. The locking mechanism on that window brings up the idea that all doors, windows, and containers could have an on/off locking action attached to them. I believe I read a suggestion on that in the forums a while ago. In Minecraft, you can set up doors and chests to only open if you have a certain named item in your possession. An actual key would be nice for each door, but I think we'd be going insane over having to carry around a boatload of keys on us. Instead, it could be set that the doors, windows, and containers could be automatically (un)locked by the creators of these items.

Admittedly, it would be interesting to eventually have both digital and manual combination locks, such as on safes.

I've been playing single player so far so not thought of keys

Heheh Bears with "master keys" aside, I know the feeling. But were we to play on multiplayer servers, they would be very handy against those pesky brigands Red wants to bring in. At least until dynamite arrives.

Quote from Darwin_Blackwolf

That would be a nice addition. The locking mechanism on that window brings up the idea that all doors, windows, and containers could have an on/off locking action attached to them. I believe I read a suggestion on that in the forums a while ago. In Minecraft, you can set up doors and chests to only open if you have a certain named item in your possession. An actual key would be nice for each door, but I think we'd be going insane over having to carry around a boatload of keys on us. Instead, it could be set that the doors, windows, and containers could be automatically (un)locked by the creators of these items.

Admittedly, it would be interesting to eventually have both digital and manual combination locks, such as on safes.

agreed also i would love have keys - i would run the motel so i dont like i have to be on to add the person to command for door - more easier is have Motel Npc to give out keys and they have to return the key back to Npc or me - its can be configured

also sliding doors would be nice - automatic or manual

Pretty good