We've been tweaking the Deep Dark biome placement criteria, as well as changing how the patches distribute in the biome. I came across this mind-blowing sight today of these two biomes colliding: http://pbs.twimg.com/media/FM8caZwXMAQx_uF.jpg
Just to calm your expectations: the bone blocks are a test where we were seeing what it would look like if normal fossils might generate in the Deep Dark exposed. No idea if we'll actually use that idea.
@SayDaysREAL It's not about the textures - 1.19.4 is in pre-release and we can't make major changes to features. There is possibility to do this sort of work in 1.20 or beyond, but right now we're locking down content.
@SayDaysREAL Also, potions are horrible in that they are all the same "item". Having different item models/textures for each potion variant is actually not simple without also exploding the model data. We don't have great support for item models based on NBT permutations.