Since C418 Is Working on New Music For Minecraft It Would Be Very Beneficial. Dynamic Sounds Would make the Games Sounds stopped or dampened by specific block types or etc. If we got an Ambiance Update that added these styled things Along these lines it would fit mostly into vanilla very well:

Block Sounds Concept Ideas:

https://www.youtube.com/watch?v=9knwvGX_S4g

Sounds Concept For Ambience – Very Old Video 2012:

https://www.youtube.com/watch?v=NVOU9fg5KbA

Thought this was a nice touch idea:

https://www.youtube.com/watch?v=MTNqbXeVJpo

Since there redoing so many textures they could possibly add new sounds for existing blocks and expand the ambiance

Things such as Nether Caves, End, and Possibly have separate sounds for Oceans and Ocean Monuments or Specific monuments or structures could give off their own feelings and experiences if they did this. Would be nice to get these done now while the textures get revamped Plus C418 is working on music for the game hopefully they are already doing this?

I Am aware I could make a mod pack for these things or make new update versions of these mods but many of these small touches would fit into 1.13's texture overhaul Plus having more ambiance in the game would be a very nice touch to the game. After playing the game 8 years I prefer to play vanilla more than modded so anything new like textures finally being more stream line and cohesive feels nice and is welcomed by me.