When specifying multiple rotation axes within a blockstate, the "z" axis is ignored.

Example:

{
	"variants": {
		"": { "model": "foobar", "z": 90 }
	}
}

This will not rotate the block 90°.

This makes it impossible to have certain visual results without creating more files. For example turning planks 90 degrees on the z axis would change the planks on all sides, making north, south, east and west vertical, but using x (and y), 2 sides will always have horizontal lines.