Note Blocks are pretty cool! I mean, they allow you to create actual songs in Minecraft...
But, the default sound of the note block is a "piano". Well, if you compare the Minecraft piano sound with a RL piano, you will see that they are very, very different.
Lapis Blocks are pretty useless, their only use could be that you can store lapis in it, but I don't see that as a really useful thing.
So, what if a Noteblock + Lapis Block = a Grand Piano?
This would open up a space for an instrument that wasn't really in the game. The grand piano sounds would be awesome!
Here's the post in r/minecraftsuggestions: https://www.reddit.com/r/minecraftsuggestions/comments/ax22wg/note_block_lapis_block_grand_piano_sounds/ (+220 votes btw!)