Things that REALLY need to be in the Minecraft 1.20 update:

• azalea wood
• fixing the way red sand generates (it only generates in a single layer, making it impossible to do anything with it without demolishing a mesa biome) and the way red sandstone generates (it doesn't, at all)
• adding mud, packed mud, moss carpets, and moss to existing "older" biomes where appropriate
• reeds or cattails for swamps, which can be harvested to craft into thatch blocks for thatch roofs
• shelf fungi
• aging mechanic similar to copper where cobblestone can become mossy cobblestone over time, and then Mossier Cobblestone that can be sheared for moss carpets
• fruit trees. The mangrove propagules have set the stage for apple trees that you can actually pick apples from. Please
• Icicles

In fact I would be perfectly happy if the update was JUST this stuff. no new mobs no new mechanics just making the world look nicer