The underground in 21w10a is almost perfect

I've been playing survival for awhile in the latest snapshots and I'm loving everything so far! The cave sizes are fantastic, and the recent ore tweaks to iron and diamond really spice up the early game.

I found myself exploring and diving deep into the caves for more rewards, and never felt like I was progressing either too quickly or too slowly. Diamonds being in smaller blobs made it really fun to keep looking for more in the caves, and iron spawning deeper in the world made early exploration really thrilling, since I knew I needed to take risks in order to progress.

Caves are just great. I love how you can have old-style spaghetti caves that are everywhere, but are a lot tighter. Finding a dead end, mining there and discovering an opening where the cave keeps going is an awesome experience. I never really felt like I was running out of places to conquer and adventure in when underground, I can't imagine how amazing the experience will be with biomes. Thank you.

The only things I'd tweak;

• I'd increase the size of iron blobs spawning above Y = 120. I think that'd be a really great way to compensate for there being less iron underground.
• More lava deep underground could also be an interesting direction.