Hello!
You said me you didn't plan to add multiple layers on slabs and stairs, so I make a suggestion.
It would be nice to have this feature, as it will add consistency to the mod, as we can put multiple layers on plants and fences.
During snow storms, it looks super nice in the nature but when we look at a house, it looks weird if the roof has full blocks and stairs. On my auberge for example:

That would be awesome to have multiple layers, and would really make the snowy builds fancier!