I started looking into ways of implementing AO in Vanillaccurate, but using the new 1.2 revision of the LabPBR standard.
I used Kappa shader as a testbed for this. Here’s how it turned out.
AO (Ambient Occlusion) is supposed to attenuate the light inside crevices and overall when light is somehow impeded from reaching a place like a recessed corner. This technique (as the name implies) doesn’t apply on direct light like sunlight but only on ambient light. It gives structure and volume to blocks, the same way default Minecraft shades the block sides a bit darker :

So without further ado, the comparison between no AO and LabPBR 1.1 format, with texture AO and LabPBR 1.2 format support. Using Kappa 2.0 shader.

This is an exaggerated case just so it’s more apparent, but the final result will of course be much more subtle.
This sets the future for Vanillaccurate, when all blocks are designed (and next versions as well, when optifine releases for those, can’t wait to design the new Nether!) I’ll probably look into upgrading the pack to LabPBR 1.2 and adding AO.