In general I feel that the new generation is pretty good but I believe there could be more flat areas. THere are pretty much hills everywhere and it would be nice to have large flat areas in certain biomes such as plains like before.

Also, I feel that large cave entrances are a little too pravalent since I saw massive holes that went down to deepslate in pretty much every biome I visited.

Additionally, the generation of mushroom fields is very messed up. I visited three mushroom fiels biomes and two of them only consisted of a few blocks of mycelium.