I have an idea on how to fix the janky movement with stairs.

[link12313]

The way minecraft does it is by having the stairs hitbox be shaped like a ramp. If the hitbox was two ramps one for each step it may move cleaner then the current system we have now.
Here are pictures of the current way you move up stairs and the new way I propose.

[l33tmaan]

I fully agree, moving up stairs feels weird and slow at the moment.
Now if you could climb regular blocks, then you could keep the janky movement for those...

[wostrelcam]

The issue is not just stairs.  Any block that is short enough for upward motion is affected.  That includes blocks that are chiseled, as well.  It would require something more along the lines of averaging the heights of lots of voxels surrounding the center of the player.

[Borgie]

If you chisel a stair-block into a ramp using the smallest block size the motion is actually quite smooth.  It does take a long time, and destroys your chisels.  You also cannot sprint up these stairs.