Rotation of Hanging Sign Under Solid Block

This suggestion is almost more like a bug report, but I assume it's an intentional game design that I think should be revisited.
Currently, hanging signs can be hung from each other, and when those subsequent signs are placed, they can be rotated at 22.5 degree increments, similar to mob heads and traditional signs. This same rotation can be also be achieved when hanging the sign from underneath a less-than-full block, like the bottom of a vertical chain, iron bar, lightning rod, or end rod. But, when trying to hang the sign beneath any full block, the rotation becomes limited to the 4 cardinal directions, north, south, east, and west, and it's model is replaced with two sets of chains that hang directly from above the sign.

This is a behavior that I find very un-intuitive. The only way to hang a sign at any other 22.5 degree angle is to first place the hanging sign underneath another hanging sign or other non-full block, then use commands to replace it with a full block.

I suggest that a hanging sign should be able to be placed at any 22.5 degree angle beneath a full block. When facing 90 degree angles, it should default to the parallel chains model, but at any other angle should switch the rotated model.

Below is an example of my proposed idea.