I have been testing out the new 1.8 Prereleases so far and enjoyed all the new features and definitely am inspired to build with the new blocks. As this post suggests I think adding 3 X 3 doors would complete the set for all different door sizes that most people would use. So far, there is 1 X 2 doors like we had in in previous versions and new 2 X 2 gates, 1 X 3 doors, and 2 x 4 gates but no doors that could fill the in-between for the medium doors to the very large gates.
I suggest we have an all-in-one door where you place it down with the center block being the middle of the two doors and they swing open like two doors next to each other. This door being all-in-one should make it easier to code in and place down than having two 1-1/2 size doors that connect. Plus, it being a single block you could also make the door more rounded at the top with the corners being part of a frame adding more detail to this door.
Another reason I believe this door would be a great addition is due to a lot of people's builds accommodating for single block doors instead of two block doors. This would also allow for nice wide 3 X 3 hallways using this door to make it feel more natural of a build than a small dinky 1 X 2 door to connect the hallway. I believe a good crafting recipe could be 8 out of 9 squares of the grid are 3 wood planks per square of the type of wood you want, and one corner square is 6 nails & strips.
I would love to hear what everyone's thoughts are for this and if anyone would like to see a 3 X 3 door in the future.