I would love to see a way for turtles to have more control over the placement of stairs, torches, logs, chests and other blocks that are influenced by the direction they are placed in.

How the feature/change should work
Currently there is some base logic on the way these blocks are placed. Example for slabs:
turtle.place() defaults to the bottom placement,
turtle.placeUp() defaults to the bottom placement
turtle.placeDown() defaults to the top placement.
When there is a block below the position the slab will be placed in it, the slab will be placed in the bottom
Otherwise when there is a block above the position the slab will be placed in it, the slab will be placed in the top

For stairs it also depends on the surrounding blocks, and maybe the direction of the turtle. In my opinion the way this works is really confusing. My suggestion would be to have the turtle.place*() functions allow for parameters x, y and z.
It should default to the way a turtle places at the moment so existing systems won't break down and things won't become more difficult for the beginners.

The effect of x, y and z should be decided by greater than 0, less than 0 and equals 0. How these values should be interpreted is up for discussion (see below)

Some rationale/use case for a feature.
Having more control over the placement of blocks we can make turtles build more advanced structures without having to do strange movements, block placing/destroying/placing.

Discussion points:
How should the values be interpreted?